FULLTEXT DEL 4 AV 5
10-K – 2026-02-12 – alny-20251231.htm
Total current assets 4,050,662 3,295,285 Property, plant and equipment, net 513,147 502,784 Operating lease right-of-use assets 194,916 191,148 Deferred tax assets 125,975 116,863 Restricted investments 22,170 68,593 Other assets 59,461 65,310 Total assets $ 4,966,331 $ 4,239,983 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities: Accounts payable $ 115,721 $ 88,415 Accrued expenses 1,080,197 793,692 Operating lease liabilities 45,518 41,886 Deferred revenue 4,845 55,481 Liabilities related to the sale of future royalties and development funding 220,068 113,018 Development derivative liability — 93,780 Total current liabilities 1,466,349 1,186,272 Operating lease liabilities, net of current portion 225,087 229,541 Convertible debt 1,007,784 1,024,621 Liabilities related to the sale of future royalties and development funding, net of current portion 1,470,341 1,334,353 Development derivative liability, net of current portion — 393,139 Other liabilities 7,594 4,969 Total liabilities 4,177,155 4,172,895 Commitments and contingencies (Note 13) Stockholders' equity: Preferred stock, $ 0.01 par value per share, 5,000 shares authorized and no shares issued and outstanding as of December 31, 2025 and December 31, 2024 — — Common stock, $ 0.01 par value per share, 250,000 shares authorized as of December 31, 2025 and December 31, 2024, respectively; 132,376 shares issued and outstanding as of December 31, 2025; 129,294 shares issued and outstanding as of December 31, 2024 1,324 1,293 Additional paid-in capital 7,510,473 7,388,061 Accumulated other comprehensive loss ( 20,097 ) ( 34,518 ) Accumulated deficit ( 6,702,524 ) ( 7,287,748 ) Total stockholders' equity 789,176 67,088 Total liabilities and stockholders' equity $ 4,966,331 $ 4,239,983 The accompanying notes are an integral part of these consolidated financial statements. 93 Table of Contents ALNYLAM PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (In thousands, except per share amounts) Years Ended December 31, 2025 2024 2023 Statements of Operations Revenues: Net product revenues $ 2,986,549 $ 1,646,228 $ 1,241,474 Net revenues from collaborations 553,366 510,221 546,185 Royalty revenue 174,022 91,794 40,633 Total revenues 3,713,937 2,248,243 1,828,292 Operating costs and expenses: Cost of goods sold 677,166 306,513 268,216 Cost of collaborations and royalties 4,705 16,857 42,190 Research and development 1,319,775 1,126,232 1,004,415 Selling, general and administrative 1,210,713 975,526 795,646 Total operating costs and expenses 3,212,359 2,425,128 2,110,467 Income (loss) from operations 501,578 ( 176,885 ) ( 282,175 ) Other expense: Interest expense ( 252,627 ) ( 141,858 ) ( 121,221 ) Interest income 111,470 121,992 95,561 Loss related to convertible debt ( 42,473 ) — — Other income (expense), net 5,204 ( 180,624 ) ( 125,682 ) Total other expense, net ( 178,426 ) ( 200,490 ) ( 151,342 ) Income (loss) before income taxes 323,152 ( 377,375 ) ( 433,517 ) (Provision for) benefit from income taxes ( 9,405 ) 99,218 ( 6,725 ) Net income (loss) $ 313,747 $ ( 278,157 ) $ ( 440,242 ) Net income (loss) per common share — basic $ 2.39 $ ( 2.18 ) $ ( 3.52 ) Net income (loss) per common share — diluted $ 2.33 $ ( 2.18 ) $ ( 3.52 ) Weighted-average common shares — basic 131,004 127,651 124,906 Weighted-average common shares — diluted 134,684 127,651 124,906 Statements of Comprehensive Income (Loss) Net income (loss) $ 313,747 $ ( 278,157 ) $ ( 440,242 ) Other comprehensive income (loss): Unrealized gains (losses) on marketable securities 1,816 ( 4 ) 11,018 Foreign currency translation gains (losses) 11,624 ( 9,643 ) 11,922 Defined benefit pension plans, net of tax 981 ( 1,496 ) ( 1,661 ) Total other comprehensive income (loss) 14,421 ( 11,143 ) 21,279 Comprehensive income (loss) $ 328,168 $ ( 289,300 ) $ ( 418,963 ) The accompanying notes are an integral part of these consolidated financial statements. 94 Table of Contents ALNYLAM PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT) (In thousands) Common Stock Additional Paid-in Capital Accumulated Other Comprehensive Loss Accumulated Deficit Total Stockholders' (Deficit) Equity Shares Amount Balance as of December 31, 2022 123,925 $ 1,240 $ 6,454,540 $ ( 44,654 ) $ ( 6,569,349 ) $ ( 158,223 ) Exercise of common stock options, net of tax withholdings 1,162 12 114,237 — — 114,249 Issuance of common stock under equity plans 707 7 16,421 — — 16,428 Stock-based compensation expense — — 225,865 — — 225,865 Other comprehensive income — — — 21,279 — 21,279 Net loss — — — — ( 440,242 ) ( 440,242 ) Balance as of December 31, 2023 125,794 1,259 6,811,063 ( 23,375 ) ( 7,009,591 ) ( 220,644 ) Exercise of common stock options, net of tax withholdings 2,504 25 284,256 — — 284,281 Issuance of common stock under equity plans 996 9 17,425 — — 17,434 Stock-based compensation expense — — 275,317 — — 275,317 Other comprehensive loss — — — ( 11,143 ) — ( 11,143 ) Net loss — — — — ( 278,157 ) ( 278,157 ) Balance as of December 31, 2024 129,294 1,293 7,388,061 ( 34,518 ) ( 7,287,748 ) 67,088 Cumulative effect adjustment from adoption of ASU 2025-07 — — — — 271,477 271,477 Exercise of common stock options, net of tax withholdings 1,836 18 229,679 — — 229,697 Issuance of common stock under equity plans 1,246 13 20,484 — — 20,497 Stock-based compensation expense — — 352,745 — — 352,745 Repurchase of 1.00 % Convertible Senior Notes due 2027 — — ( 445,185 ) — — ( 445,185 ) Purchase of capped calls related to 0.00 % Convertible Senior Notes due 2028 — — ( 35,311 ) — — ( 35,311 ) Other comprehensive income — — — 14,421 — 14,421 Net income — — — — 313,747 313,747 Balance as of December 31, 2025 132,376 $ 1,324 $ 7,510,473 $ ( 20,097 ) $ ( 6,702,524 ) $ 789,176 The accompanying notes are an integral part of these consolidated financial statements. 95 Table of Contents ALNYLAM PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF CASH FLOWS (In thousands) Years Ended December 31, 2025 2024 2023 Cash flows from operating activities: Net income (loss) $ 313,747 $ ( 278,157 ) $ ( 440,242 ) Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Depreciation and amortization 55,658 56,670 54,054 Non-cash interest expense on liabilities related to the sale of future royalties and development funding 238,399 127,133 106,554 Stock-based compensation expense 348,235 272,084 221,680 Realized and unrealized loss on marketable equity securities 2,306 3,022 16,944 Loss related to convertible debt 42,473 — — Change in fair value of development derivative liability — 170,770 90,997 Deferred income taxes ( 2,198 ) ( 106,762 ) ( 713 ) Other ( 29,758 ) ( 38,988 ) ( 2,379 ) Changes in operating assets and liabilities: Accounts receivable, net ( 359,963 ) ( 86,550 ) ( 87,939 ) Inventory 8,474 13,590 18,367 Prepaid expenses and other assets ( 117,724 ) 3,229 ( 9,029 ) Accounts payable, accrued expenses and other liabilities 75,066 91,093 80,840 Deferred revenue ( 50,635 ) ( 235,446 ) 55,022 Net cash provided by (used in) operating activities 524,080 ( 8,312 ) 104,156 Cash flows from investing activities: Purchases of property, plant and equipment ( 58,697 ) ( 34,277 ) ( 62,211 ) Purchases of marketable securities ( 1,305,081 ) ( 1,634,911 ) ( 1,823,501 ) Sales and maturities of marketable securities 1,802,257 1,571,665 1,553,800 Proceeds from maturity of restricted investments 59,775 57,875 58,475 Purchases of restricted investments ( 59,775 ) ( 77,075 ) ( 58,475 ) Other investing activities ( 2,150 ) ( 117 ) ( 4,438 ) Net cash provided by (used in) investing activities 436,329 ( 116,840 ) ( 336,350 ) Cash flows from financing activities: Proceeds from issuance of 0.00 % Convertible Senior Notes due 2028, net 645,692 — — Purchases of capped calls related to 0.00 % Convertible Senior Notes due 2028 ( 35,311 ) — — Repayment of 1.00 % Convertible Senior Notes due 2027 ( 1,154,913 ) — — Payment of issuance costs for revolving credit agreement ( 2,414 ) — — Proceeds from exercise of stock options and other types of equity, net 250,028 302,951 147,464 Proceeds from liabilities related to the sale of future royalties and development funding 6,000 — — Repayment of liabilities related to the sale of future royalties and development funding ( 14,272 ) — — (Repayment of) proceeds from development derivative liability, net — ( 8,792 ) 24,667 Net cash (used in) provided by financing activities ( 305,190 ) 294,159 172,131 Effect of exchange rate changes on cash, cash equivalents and restricted cash 34,936 ( 15,239 ) 6,391 Net increase (decrease) in cash, cash equivalents and restricted cash 690,155 153,768 ( 53,672 ) Cash, cash equivalents and restricted cash, beginning of period 968,652 814,884 868,556 Cash, cash equivalents and restricted cash, end of period $ 1,658,807 $ 968,652 $ 814,884 Supplemental disclosure of cash flows: Cash paid for interest $ 218,707 $ 67,578 $ 32,118 Operating lease right-of-use assets obtained in exchange for new operating lease liabilities $ 21,195 $ 9,309 $ 2,570 Supplemental disclosure of noncash investing activities: Capital expenditures included in accounts payable and accrued expenses $ 10,902 $ 2,324 $ 3,805 The accompanying notes are an integral part of these consolidated financial statements. 96 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 1. NATURE OF BUSINESS Alnylam Pharmaceuticals, Inc. (also referred to as Alnylam, the Company, we, our or us) commenced operations on June 14, 2002 as a biopharmaceutical company seeking to develop and commercialize novel therapeutics based on ribonucleic acid interference, or RNAi. We are committed to the advancement of our company strategy of building a multi-product, global, commercial biopharmaceutical company with a deep and sustainable clinical pipeline of RNAi therapeutics for future growth and a robust, organic research engine for sustainable innovation and great potential for patient impact. Since inception, we have focused on discovering, developing and commercializing RNAi therapeutics by establishing and maintaining a strong intellectual property position in the RNAi field, establishing strategic collaborations with leading pharmaceutical and life sciences companies, generating revenues through licensing agreements, and ultimately developing and commercializing RNAi therapeutics globally, either independently or with our strategic collaborators. We have devoted substantially all of our efforts to business planning, research, development, manufacturing and commercializing biopharmaceuticals products, acquiring, filing and expanding our intellectual property rights, recruiting our management and technical staff, and raising capital. As of December 31, 2025, we have six marketed products, including two products that are commercialized by collaborators, and multiple late-stage investigational programs advancing towards potential commercialization. We currently generate worldwide product revenues from four commercialized products, AMVUTTRA, ONPATTRO, GIVLAARI and OXLUMO, primarily in the United States, or U.S., and Europe. 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements reflect the operations of Alnylam and our wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated. Certain prior period amounts in the consolidated financial statements have been reclassified to conform to the current period presentation. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. In our consolidated financial statements, we use estimates and assumptions related to our inventory valuation and related reserves, clinical accruals, liabilities related to the sale of future royalties and development funding, income taxes, deferred tax asset valuation allowances, revenue recognition, research and development expenses, and stock-based compensation expense. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known. Liquidity Based on our current operating plan, we believe that our cash, cash equivalents, marketable securities, as well as the revenue we expect to generate from product sales and under our existing collaborations, including royalties on sales of Leqvio and Qfitlia, and available borrowing capacity under the revolving credit agreement, or the Revolving Credit Agreement, as of December 31, 2025, will be sufficient to satisfy our near-term capital and operating needs for at least the next 12 months from the filing date of this Annual Report on Form 10-K. Please refer to Note 8, Convertible Debt and Other Financing, for further information related to the Revolving Credit Agreement. Concentrations of Credit Risk and Significant Customers Financial instruments that potentially expose us to concentrations of credit risk primarily consist of cash, cash equivalents and marketable securities. As of December 31, 2025 and 2024, substantially all of our cash, cash equivalents and marketable securities were invested in money market funds, certificates of deposit, commercial paper, corporate notes, U.S. government-sponsored enterprise securities and U.S. treasury securities through highly rated financial institutions. Corporate notes may also include foreign bonds denominated in U.S. dollars. Investments are restricted, in accordance with our investment policy, to a concentration limit per issuer. During the years ended December 31, 2025, 2024 and 2023, our revenues were generated primarily from product sales to customers and collaborations with strategic partners. As of December 31, 2025 and 2024, our gross accounts receivable balance was comprised of payments primarily due from customers for product sales and our collaborators. 97 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS The following table summarizes customers that represent 10% or greater of our consolidated total gross revenues: Years Ended December 31, 2025 2024 2023 Distributor A 45 % 29 % 28 % Roche * * 15 % Regeneron Pharmaceuticals * 11 % * __________________________________________ * Represents less than 10% and/or not a customer in the applicable year The following table summarizes customers with amounts due that represent 10% or greater of our consolidated gross accounts receivable balance: As of December 31, 2025 2024 Distributor A 45 % 16 % Novartis AG * 23 % Fair Value Measurements The fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are observable, such as quoted prices (adjusted), interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. The fair value hierarchy level is determined by the lowest level of significant input. Investments in Marketable Securities and Cash Equivalents We invest our excess cash balances in marketable debt securities and classify our investments as either trading, held-to-maturity or available-for-sale based on facts and circumstances present at the time we purchased the securities. As of December 31, 2025 and 2024, we classified all of our investments in debt securities as available-for-sale and as current assets on the consolidated balance sheets as they represent the investment of funds available for current operations. We report available-for-sale debt securities at fair value at each balance sheet date, for which fair value measurement data is obtained from independent pricing services, and include any unrealized holding gains and losses (the adjustment to fair value) in accumulated other comprehensive loss. Realized gains and losses are determined using the specific identification method and are included in other income (expense), net. If any adjustment to fair value reflects a decline in the value of the marketable debt securities, we consider all available evidence to evaluate if an impairment loss exists, and if so, mark the investment to market through a charge to our consolidated statements of operations and comprehensive income (loss). We did not record any impairment charges related to our marketable debt securities during the years ended December 31, 2025, 2024 or 2023. Our marketable debt securities are classified as cash equivalents if the original maturity, from the date of purchase, is 90 days or less, and as marketable debt securities if the original maturity, from the date of purchase, is in excess of 90 days. Our cash equivalents are generally composed of commercial paper, corporate notes, U.S. government-sponsored enterprise securities, U.S. treasury securities, money market funds and certificates of deposit. We measure marketable equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of an investee), which have readily available prices, at fair value with changes in fair value recognized in other income (expense), net on our consolidated statements of operations and comprehensive income (loss). Accounts Receivable, Net We record accounts receivable net of prompt payment discounts and chargebacks based on contractual terms. As of December 31, 2025 and 2024, based on our estimation of expected write-offs, we determined an allowance for doubtful accounts was not material. We have standard payment terms that generally require payment within approximately 30 to 90 days. Accounts receivable, net on our consolidated balance sheets also includes collaboration receivables and royalty receivables. Inventory Inventory is measured at the lower of cost or estimated net realizable value and classified based on the anticipation of when it will be consumed either within our normal operating cycle (short-term) or beyond (long-term). We use a standard cost basis, which approximates cost determined on a first-in, first-out basis. Inventory costs include all raw materials, direct conversion 98 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS costs and overhead. Raw and intermediate materials that may be used for either research and development or commercial purposes are classified as inventory until the material is consumed or otherwise allocated for research and development. If the material is used for research and development, it is recorded as research and development expenses once that determination is made. We capitalize inventory costs that are expected to be sold commercially once we determine it is probable that the inventory costs will be recovered through commercial sale based on the review of several factors, including (i) the likelihood that all required regulatory approvals will be received, considering any special filing status, (ii) the expected timing of validation (if not yet completed) of manufacturing processes in the associated facility, (iii) the expected expiration of the inventory, (iv) logistical or commercial constraints that may impede the timely distribution and sale of the product, including transport requirements and reimbursement status, (v) current market factors, including competitive landscape and pricing, (vi) threatened or anticipated litigation challenges, (vii) history of approvals of similar products or formulations, and (viii) U.S. Food and Drug Administration, or FDA, (or other appropriate regulatory agencies) correspondence regarding the safety and efficacy of the product. Prior to the capitalization of inventory costs, we record such costs as research and development expenses on our consolidated statements of operations and comprehensive income (loss). We reduce our inventory to net realizable value for potentially excess, dated or obsolete inventory based on our quarterly assessment of the recoverability of our capitalized inventory. We periodically review inventory levels to identify what may expire prior to expected sale or has a cost basis in excess of its estimated realizable value and write down such inventories as appropriate. Property, Plant and Equipment, Net Property, plant and equipment are stated at cost, net of accumulated depreciation. Depreciation expense is recorded on a straight-line basis over the estimated useful life of the asset. Construction in progress reflects amounts incurred for construction or improvements of property, plant or equipment that have not been placed in service. Costs of construction of certain long-lived assets include capitalized interest, which is amortized over the estimated useful life of the related asset. The cost and accumulated depreciation of assets retired or sold are removed from the respective asset category, and any gain or loss is recognized in our consolidated statements of operations and comprehensive income (loss). During the years ended December 31, 2025, 2024 and 2023, we recorded $ 54.8 million, $ 55.1 million and $ 51.6 million, respectively, of depreciation expense related to our property, plant and equipment. The estimated useful lives of property, plant and equipment are as follows: Asset Category Useful Life Laboratory equipment 5 years Computer equipment and software 3 - 10 years Furniture and fixtures 5 years Leasehold improvements Shorter of asset life or lease term Manufacturing equipment 7 - 15 years Buildings 40 years Leases We determine if an arrangement is a lease at contract inception based on the facts and circumstances present in the arrangement. All of our leases are classified as operating leases. Operating lease right-of-use assets represent our right to use an underlying asset for the lease term and operating lease liabilities represent our obligation to make lease payments arising from the leasing arrangement. Operating lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, in determining the operating lease liabilities, we use an estimate of our incremental borrowing rate based on the information available at commencement. Operating lease right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments less lease incentives. Single lease cost is recognized on a straight-line basis over the lease term. We do not separate non-lease components from lease components for all classes of underlying assets. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets, and the respective lease cost is recognized in the consolidated statements of operations and comprehensive income (loss) on a straight-line basis over the term of the lease. Clinical Accruals We record accrued liabilities related to products we have received or services that we have incurred, specifically related to ongoing preclinical studies and clinical trials, for which service providers have not yet billed us, or when billing terms under these contracts do not coincide with the timing of when the work is performed, on our consolidated balance sheets. These costs 99 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS primarily relate to third-party clinical management costs, laboratory and analysis costs, toxicology studies and investigator fees. The assessment of these costs requires judgment based on our knowledge of the research and development programs, services performed for the period, experience with related activities and the expected duration of the third-party service contract, where applicable. Revenue Recognition We recognize revenue when control of promised goods or services is transferred to a customer at an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. To determine revenue recognition, we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) we satisfy the performance obligation(s). We only apply the five-step model to contracts when collectability of the consideration to which we are entitled in exchange for the goods or services we transfer to the customer is determined to be probable. At contract inception, once the contract is determined to be within the scope of Accounting Standards Codification, or ASC, Topic 606, Revenue from Contracts with Customers , or ASC 606, we assess whether the goods or services promised within each contract are distinct and, therefore, represent a separate performance obligation. Goods and services that are determined not to be distinct are combined with other promised goods and services until a distinct bundle is identified. We then allocate the transaction price (the amount of consideration we expect to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognize the associated revenue when (or as) each performance obligation is satisfied. Our estimate of the transaction price for each contract includes all variable consideration to which we expect to be entitled. Amounts are recorded as accounts receivable when our right to consideration is unconditional. We do not assess whether a contract has a significant financing component if the expectation at contract inception is that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. We expense incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that we would have recognized is one year or less or the amount is immaterial. As of December 31, 2025 and 2024, we had not capitalized any costs to obtain any of our contracts. Net Product Revenues Our net product revenues are recognized, net of variable consideration related to certain allowances and accruals, at the time the customer obtains control of our product. We use the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, or the most likely amount method, which is the single most likely amount in a range of possible considerations, to estimate variable consideration related to our product sales. We use the expected value method to estimate variable consideration for certain rebates, chargebacks, product returns, and other incentives and we use the most likely amount method for certain rebates, trade discounts and allowances. We record reserves, based on contractual terms, for components related to product sold during the reporting period, as well as our estimate of product that remains in the distribution channel inventory at the end of the reporting period that we expect will be sold to qualified healthcare providers. On a quarterly basis, we update our estimates and record any needed adjustments in the period we identify the adjustments. The following are the components of variable consideration related to product revenues: Chargebacks : We estimate obligations resulting from contractual commitments with the government and other entities to sell products to qualified healthcare providers at prices lower than the list prices charged to the customer who directly purchases from us. The customer charges us for the difference between what it pays to us for the product and the selling price to the qualified healthcare providers. We estimate chargebacks that we expect to pay and deduct the chargeback amount in full from gross product revenues and accounts receivable at the time we recognize the related revenues. Rebates : We are subject to discount obligations under government programs, including Medicare and Medicaid in the U.S. and similar programs in certain other countries, including countries in which we are accruing for estimated rebates because final pricing has not yet been negotiated. We are also subject to potential rebates in connection with our value-based agreements with certain commercial payors. We record reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of product revenues and a current liability that is included in accrued expenses on our consolidated balance sheet. Our estimate for rebates is based on statutory discount rates, expected utilization or an estimated number of patients on treatment, as applicable. Other incentives and allowances: Other incentives and allowances include trade discounts and allowances, fees, product returns, and co-payment assistance that we provide to patients with commercial insurance that have coverage and reside in states that allow co-payment assistance. We estimate discounts and fees based on contract terms and other relevant factors, and deduct these discounts and fees in full from gross product revenues and accounts receivable at the time we recognize the related revenues. We estimate the amount of product that will be returned based on our sales history for product that is damaged, 100 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS defective or expired in accordance with the terms of each customer agreement, and we estimate the average co-payment assistance amounts for our products based on expected customer demographics. We record any such amounts within accrued expenses or product accounts receivable on our consolidated balance sheets. Net Revenues from Collaborations We earn revenue in connection with collaboration agreements that allow our collaborators to utilize our technology platforms and develop product candidates. Our significant collaboration agreements are detailed in Note 4, Net Revenues from Collaborations. For each collaborator, we discuss our revenue recognition, including our significant performance obligations under each agreement. At contract inception, we assess whether the collaboration arrangements are within the scope of ASC 606 or ASC Topic 808, Collaborative Arrangements , or ASC 808, to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed based on the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of ASC 808 that contain multiple elements, we first determine which elements of the arrangement are within the scope of ASC 808 and which elements are within the scope of ASC 606. For elements of collaboration arrangements that are accounted for pursuant to ASC 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For elements of collaboration arrangements that are accounted for pursuant to ASC 606, we identify the performance obligations and allocate the total consideration we expect to receive on a relative standalone selling price basis to each performance obligation. Variable consideration, such as performance-based milestones, will be included in the total consideration if we expect to receive such consideration and if it is probable that the inclusion of the variable consideration will not result in a significant reversal in the cumulative amount of revenue recognized under the arrangement. Our estimate of the total consideration we expect to receive under each collaboration arrangement is updated for each reporting period, and any adjustments to revenue are recorded on a cumulative catch-up basis. We exclude sales-based royalty and milestone payments from the total consideration we expect to receive until the underlying sales occur because the license to our intellectual property is deemed to be the predominant item to which the royalties or milestones relate as it is the primary driver of value in our collaboration arrangements. Key assumptions to determine the standalone selling price may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. We recognize revenue associated with each performance obligation as the control over the promised goods or services transfer to our collaborator which occurs either at a point in time or over time. If control transfers over time, revenue is recognized by using a method of measuring progress that best depicts the transfer of goods or services. We evaluate the measure of progress and related inputs each reporting period and any resulting adjustments to revenue are recorded on a cumulative catch-up basis. Consideration received that does not meet the requirements to satisfy ASC 808 or ASC 606 revenue recognition criteria is recorded as deferred revenue in the accompanying consolidated balance sheets, classified as either short-term (less than 12 months) or long-term (more than 12 months) deferred revenue based on our best estimate of when such revenue will be recognized. Cost of Goods Sold Cost of goods sold includes the cost of producing and distributing inventories that are related to product revenues during the respective period (including salaries and related costs, stock-based compensation expenses and benefits for employees involved with production and distribution, supplies, external services, freight and indirect overhead costs), third-party royalties payable on our net product revenues and amortization of intangible assets associated with the sale of our products. Cost of goods sold may also include costs related to excess or obsolete inventory adjustment charges, abnormal costs, unabsorbed manufacturing and overhead costs, and manufacturing variances. Cost of Collaborations and Royalties Cost of collaborations and royalties includes costs we incur in connection with providing commercial drug supplies, such as GalNAc material, to collaborators, in addition to royalties we owe to third parties on the net sales of licensed products. Income Taxes We account for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. 101 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Uncertain tax positions, for which management’s assessment is that there is a more than 50% probability of sustaining the position upon challenge by a taxing authority based upon its technical merits, are subject to certain recognition and measurement criteria. The nature of the uncertain tax positions is often very complex and subject to change, and the amounts at issue can be substantial. We develop our cumulative probability assessment of the measurement of uncertain tax positions using internal experience, judgment and assistance from professional advisors. We re-evaluate these uncertain tax positions on a quarterly basis based on a number of factors including, but not limited to, changes in facts or circumstances, changes in tax law, and effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision. Research and Development Expenses We record research and development expenses as incurred. Included in research and development expenses are salaries and related costs, stock-based compensation expenses, benefits and other operating costs, facilities, supplies, external services, clinical trial and manufacturing costs, certain costs related to our collaboration arrangements, and overhead directly related to our research and development operations, as well as costs to acquire technology licenses. We have entered into several license agreements for rights to utilize certain technologies. The terms of the licenses may provide for upfront payments, annual maintenance payments, milestone payments based upon certain specified events being achieved and royalties on product sales. We charge costs to acquire and maintain licensed technology that has not reached technological feasibility and does not have alternative future use to research and development expenses as incurred. Stock-Based Compensation We recognize stock-based compensation expense for grants under our stock incentive plans and employee stock purchase plan. We account for all stock-based awards granted to employees at their fair value and recognize compensation expense over each employee’s requisite service period, which is generally the vesting period of the award. Determining the amount of stock-based compensation to be recorded requires us to develop estimates of fair values of stock awards as of the grant date. We calculate the grant date fair values of stock options using the Black-Scholes valuation model, which requires us to make assumptions, including but not limited to expected stock price volatility over the term of the awards and the expected term of stock options. The fair value of restricted stock awards granted to employees is based upon the quoted closing market price per share on the date of grant. We have performance conditions included in certain of our restricted stock awards that are based upon the achievement of pre-specified clinical development, regulatory, commercial and/or financial performance events. As the outcome of each event has inherent risk and uncertainties, and a positive outcome may not be known until the event is achieved, we begin to recognize the grant-date fair value of the performance-based restricted stock awards when we determine the achievement of each performance condition is deemed probable, a determination which requires significant judgment by management. On the date the performance condition is deemed probable, we record a cumulative expense catch-up, with remaining expense amortized over the remaining service period. The number of shares that ultimately vests for certain performance-based restricted stock units may range from 0 % to 200 % of the target award, depending on the assessed level of achievement of the specified performance conditions. We reassess the probability of achievement at each reporting period and adjust cumulative expense as necessary. Advertising Expenses We expense the costs of advertising as incurred. Advertising expenses were $ 36.0 million, $ 29.7 million and $ 12.4 million for the years ended December 31, 2025, 2024 and 2023, respectively. Liabilities Related to the Sale of Future Royalties and Development Funding When we enter into or modify an arrangement with a party to fund our research and development costs, we assess if the arrangement meets all of the characteristics of a derivative or contains an embedded derivative, and if so, whether any of the scope exceptions to derivative accounting are applicable. If the arrangement is not accounted for as a derivative, we assess if successful completion of the research and development is already probable at the time the funding is received, and if so we apply the guidance in ASC Topic 470-10, Debt - Overall , or ASC 470-10. If the research and development risk is substantive, such that it is not yet probable development will be successful, we apply the guidance in ASC Topic 730-20, Research and Development - Research and Development Arrangements , or ASC 730-20, to evaluate whether the research and development funding is a liability to repay the funding party or an obligation to perform contractual services. If the transfer of financial risk involved with the research and development is substantive and genuine, and we have no explicit or implicit obligation to repay any of the funds, we account for the arrangement as an obligation to perform contractual research and development services. If the transfer of financial risk is not substantive and genuine, we recognize a liability to repay the funding party. Due to the absence of specific guidance with respect to the subsequent accounting for funds recognized as repayment obligations in ASC 730-20, we apply the concepts of ASC 470-10 to account for the liability to repay the funding party when a repayment obligation has been incurred. 102 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS We account for the liabilities related to the sale of future royalties and development funding as debt financings. Interest on these liabilities is recognized using the effective interest rate method over the repayment period. The liabilities related to the sale of future royalties and development funding and the related interest expense are based on our current estimates of future royalties and milestones expected to be paid and received over the life of the arrangement, which we determine by using third-party data to estimate Leqvio’s and AMVUTTRA’s global net revenues. At each balance sheet date, we assess the expected payments and we account for any change by prospectively adjusting the effective interest rate and related interest expense. Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income (loss) and certain changes in stockholders’ equity (deficit) that are excluded from net income (loss). Other comprehensive income (loss) includes unrealized holding gains and losses on marketable debt securities classified as available-for-sale, foreign currency translation adjustments (if the functional currency is not the U.S. dollar), and certain changes in the fair value of the plan assets and projected benefit obligations attributed to our defined benefit pension plan. Recently Adopted Accounting Pronouncements In December 2023, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2023-09, Improvements to Income Tax Disclosures , or ASU 2023-09, which requires entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. We adopted ASU 2023-09 in the fourth quarter of 2025 and applied it prospectively, as disclosed in Note 14, Income Taxes. The adoption did not have an impact on our consolidated financial statements. In November 2024, the FASB issued ASU 2024-04, Induced Conversions of Convertible Debt Instruments, or ASU 2024-04, which clarifies the requirements for determining whether certain settlements of convertible debt instruments should be accounted for as an induced conversion or extinguishment of convertible debt. We adopted ASU 2024-04 in the third quarter of 2025 and applied it on a retrospective basis as of January 1, 2025. The adoption did not have a material effect on our consolidated financial statements, but we applied the guidance to the repurchase of our 1.00 % Convertible Senior Notes due 2027 in the third and fourth quarters of 2025. Please refer to Note 8, Convertible Debt and Other Financing, for further information related to the repurchase. In September 2025, the FASB issued ASU 2025-07, Derivatives Scope Refinements and Scope Clarification for Share-Based Noncash Consideration from a Customer in a Revenue Contract , or ASU 2025-07. The guidance refines the scope of ASC Topic 815, Derivatives and Hedging , or ASC 815, to clarify which contracts are subject to derivative accounting. The guidance also provides clarification under ASC 606 for share-based payments from a customer in a revenue contract. We adopted the standard in the fourth quarter of 2025 on a modified retrospective basis as of January 1, 2025. As a result of the new derivative scope exception created by the standard, we now account for the previous development derivative liability similar to a debt obligation under the guidance of ASC 470-10. Refer to Note 9, Liabilities Related To The Sale Of Future Royalties And Development Funding, for additional information related to the adoption of this new standard and the related effects to the consolidated financial statements. We elected to adopt the guidance of ASU 2025-07 because we believe the accounting treatment of this guidance better reflects the economics of our existing research and development funding arrangements and provides more decision-useful information when derivative accounting is not applied. The guidance of ASU 2025-07 related to share-based noncash consideration received in exchange for the transfer of goods or services to a customer did not have any impact on our consolidated financial statements upon adoption. As a result of the adoption, we derecognized the development derivative liability, recognized a liability related to the sale of future royalties and development funding, and recorded a cumulative effect adjustment of $ 271.5 million as a credit to accumulated deficit as of January 1, 2025. 103 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Supplementary Quarterly Financial Information (Unaudited) The following is a summary of the unaudited prior quarterly results for the condensed consolidated statements of operations and comprehensive income (loss) reflecting the previously reported quarterly amounts and adjusted amounts after applying the new guidance of ASU 2025-07. (In thousands, except per share amounts) Previously Reported Three Months Ended March 31, 2025 Adjusted Three Months Ended March 31, 2025 Previously Reported Six Months Ended June 30, 2025 Adjusted Six Months Ended June 30, 2025 Previously Reported Nine Months Ended September 30, 2025 Adjusted Nine Months Ended September 30, 2025 Interest expense $ ( 38,646 ) $ ( 58,309 ) $ ( 78,892 ) $ ( 119,765 ) $ ( 123,290 ) $ ( 187,227 ) Other (expense) income, net ( 49,700 ) 9,191 ( 56,099 ) 18,051 ( 130,249 ) 8,564 Total other expense, net ( 59,673 ) ( 20,445 ) ( 78,832 ) ( 45,555 ) ( 207,845 ) ( 132,969 ) (Loss) income before income taxes ( 41,596 ) ( 2,368 ) ( 76,954 ) ( 43,677 ) 162,015 236,891 Net (loss) income ( 57,479 ) ( 18,251 ) ( 123,756 ) ( 90,479 ) 127,328 202,204 Net (loss) income per common share - basic ( 0.44 ) ( 0.14 ) ( 0.95 ) ( 0.70 ) 0.98 1.55 Net (loss) income per common share - diluted ( 0.44 ) ( 0.14 ) ( 0.95 ) ( 0.70 ) 0.95 1.51 Comprehensive (loss) income $ ( 60,478 ) $ ( 21,250 ) $ ( 119,190 ) $ ( 85,913 ) $ 140,071 $ 214,947 Recent Accounting Pronouncements In September 2025, the FASB issued ASU 2025-06, Targeted Improvements to the Accounting for Internal-Use Software , which modernizes the guidance for internal-use software costs by increasing the operability of the recognition guidance considering different methods of software development. The standard will be effective for annual reporting periods beginning after December 15, 2027, as well as interim period reporting periods within those annual reporting periods, with early adoption permitted. The standard updates may be applied on a prospective, retrospective, or modified retrospective approach. We are currently evaluating the impact this guidance could have on our consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Disaggregation of Income Statement Expenses , or ASU 2024-03, which is intended to improve disclosures by requiring additional information about specific expense categories in the notes to the financial statements on an annual and interim basis. The standard will be effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. The standard updates may be applied on either a prospective or retrospective basis. We are currently evaluating the disclosure requirements related to ASU 2024-03. 104 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 3. NET PRODUCT REVENUES Net product revenues, classified based on the geographic region in which the product is sold and by franchise (“TTR,” which includes AMVUTTRA and ONPATTRO, and “Rare,” which includes GIVLAARI and OXLUMO) consisted of the following: Years Ended December 31, (In thousands) 2025 2024 2023 AMVUTTRA United States $ 1,731,222 $ 630,613 $ 411,169 Europe 405,899 235,441 70,898 Rest of World 176,715 104,396 75,771 Total 2,313,836 970,450 557,838 ONPATTRO United States 62,126 74,787 97,739 Europe 79,429 134,197 210,916 Rest of World 31,234 43,873 45,891 Total 172,789 252,857 354,546 Total TTR 2,486,625 1,223,307 912,384 GIVLAARI United States 205,715 165,373 141,954 Europe 77,715 65,906 57,498 Rest of World 25,057 24,592 19,799 Total 308,487 255,871 219,251 OXLUMO United States 68,467 62,766 38,159 Europe 88,049 80,753 60,025 Rest of World 34,921 23,531 11,655 Total 191,437 167,050 109,839 Total Rare 499,924 422,921 329,090 Total net product revenues $ 2,986,549 $ 1,646,228 $ 1,241,474 As of December 31, 2025 and 2024, net product revenue-related receivables of $ 669.5 million and $ 269.9 million , respectively, were included in accounts receivable, net on our consolidated balance sheets. The following table summarizes balances and activity in each product revenue allowance and reserve category: As of December 31, 2025 (In thousands) Chargebacks and Rebates Other Incentives and Allowances Total Beginning balance $ 350,908 $ 10,908 $ 361,816 Provision related to current period sales 779,332 90,435 869,767 Provision related to prior period sales ( 48,816 ) — ( 48,816 ) Credit or payments made during the period for current year sales ( 474,781 ) ( 65,454 ) ( 540,235 ) Credit or payments made during the period for prior year sales ( 206,790 ) ( 10,092 ) ( 216,882 ) Total $ 399,853 $ 25,797 $ 425,650 105 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS As of December 31, 2024 (In thousands) Chargebacks and Rebates Other Incentives and Allowances Total Beginning balance $ 325,672 $ 20,269 $ 345,941 Provision related to current period sales 382,892 31,204 414,096 Credit or payments made during the period for current year sales ( 194,973 ) ( 34,776 ) ( 229,749 ) Credit or payments made during the period for prior period sales ( 162,683 ) ( 5,789 ) ( 168,472 ) Total $ 350,908 $ 10,908 $ 361,816 4. NET REVENUES FROM COLLABORATIONS Net revenues from collaborations consisted of the following: Years Ended December 31, (In thousands) 2025 2024 2023 Roche $ 394,881 $ 119,489 $ 337,802 Regeneron Pharmaceuticals 113,957 302,798 100,468 Novartis AG — 79,759 86,727 Other 44,528 8,175 21,188 Total net revenues from collaborations $ 553,366 $ 510,221 $ 546,185 The following table presents the balance of our receivables and contract liabilities related to our collaboration agreements: As of December 31, (In thousands) 2025 2024 Receivables included in accounts receivable, net $ 48,823 $ 102,743 Contract liabilities included in deferred revenue and deferred revenue, net of current portion $ 4,845 $ 55,481 We recognized net revenues from collaborations of $ 53.8 million and $ 266.5 million in the years ended December 31, 2025 and 2024, respectively, each of which was included in the contract liability balance at the beginning of the applicable period. To determine revenue recognized in the period from contract liabilities, we first allocate revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional consideration is received on those contracts in subsequent periods, we assume all revenue recognized in the reporting period first applies to the beginning contract liability as opposed to a portion applying to the new consideration for the period. Product Collaborations Roche On July 21, 2023, or the Effective Date, we entered into a Collaboration and License Agreement, or the Roche Agreement, with F. Hoffmann-La Roche Ltd. and Genentech, Inc., or, collectively, Roche, pursuant to which we and Roche established a worldwide, strategic collaboration for the joint development of zilebesiran. Zilebesiran is our investigational small interfering RNA, or siRNA, therapeutic targeting liver-expressed angiotensinogen, which is currently in Phase 3 clinical development for the treatment of hypertension. Under the Roche Agreement, we granted to Roche (i) co-exclusive rights to develop zilebesiran worldwide and commercialize zilebesiran in the U.S., referred to as the Co-Commercialization Territory, (ii) exclusive rights to commercialize zilebesiran outside of the U.S., referred to as the Roche Territory, and (iii) non-exclusive rights to manufacture zilebesiran for the development and commercialization of zilebesiran in the Roche Territory. We lead the global clinical development for zilebesiran. We are responsible for forty percent ( 40 %) and Roche is responsible for the remaining sixty percent ( 60 %) of development costs incurred in the conduct of development activities that support regulatory approval of zilebesiran globally. We and Roche share equally ( 50 / 50 ) all costs incurred in connection with development activities that are conducted to support regulatory approval of zilebesiran solely in the Co-Commercialization Territory if incremental development activities are needed. Roche is solely responsible for all costs incurred in the conduct of development activities that primarily support regulatory approval in the Roche Territory. Upon regulatory approval, Roche has the exclusive right to commercialize zilebesiran in the Roche Territory and will pay us tiered, low double-digit royalties based 106 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS on net sales of zilebesiran on a country-by-country basis during the applicable royalty term. We and Roche will co-commercialize zilebesiran in the Co-Commercialization Territory and share equally ( 50 / 50 ) in profits and losses (including commercialization costs). Roche has the right to terminate the Roche Agreement for any or no reason at all upon prior written notice. In addition, either party may terminate the Roche Agreement for a material breach by, or insolvency of, the other party, subject to a cure period. Unless earlier terminated pursuant to its terms, the Roche Agreement will remain in effect until expiration on a country-by-country basis (a) in the Roche Territory, upon expiration of the applicable royalty term in the applicable country and (b) in the Co-Commercialization Territory, upon expiration of the term of the co-commercialization efforts. As of the Effective Date, we identified the following promises in the Roche Agreement that were evaluated under the scope of ASC 606: (i) a co-exclusive license to develop zilebesiran worldwide and commercialize zilebesiran within the Co-Commercialization Territory, a non-exclusive license to manufacture zilebesiran in the Roche Territory solely for purposes of developing and commercializing zilebesiran in the Roche Territory, and an exclusive license to commercialize zilebesiran in the Roche Territory, collectively referred to as Roche License Obligation, (ii) development services, including the manufacture of clinical supply, that support regulatory approval of zilebesiran, referred to as the Roche Development Services Obligation, and (iii) a technology transfer of the existing manufacturing process for zilebesiran, referred to as the Roche Technology Transfer Obligation. The three performance obligations under the Roche Agreement are collectively referred to as the Roche Performance Obligations. We determined that the Roche License Obligation, Roche Development Services Obligation and Roche Technology Transfer Obligation were reflective of a vendor-customer relationship and therefore represented performance obligations within the scope of ASC 606. The Roche License Obligation was considered functional intellectual property and distinct from other promises under the contract as Roche can benefit from the licenses on its own or together with other readily available resources. As the licenses were delivered at the same time, they were considered one performance obligation at contract inception. The Roche Development Services Obligation was considered distinct as Roche could benefit from the development services together with the licenses transferred by us at the inception of the agreement. The development services are not expected to significantly modify or customize the initial intellectual property as zilebesiran was in Phase 2 of clinical development at contract inception. The Roche Technology Transfer Obligation was distinct as Roche can benefit from the manufacturing license transferred by us at the inception of the agreement given the advancements of our RNAi platform and our utilization of third-party contract manufacturing organizations to manufacture zilebesiran. Therefore, each represented a separate performance obligation within the contract with a customer under the scope of ASC 606 at contract inception. We consider the collaborative activities associated with the co-commercialization of zilebesiran in the U.S. to be a separate unit of account within the scope of ASC 808 as we and Roche are both active participants in the commercialization activities and are exposed to significant risks and rewards that are dependent on the commercial success of the activities in the arrangement. Based on the standalone selling prices of each performance obligation as of the Effective Date, we allocated the variable consideration related to the estimated reimbursements for the Roche Development Services Obligation and the Roche Technology Transfer Obligation to each performance obligation as the terms of the variable payment relate specifically to our efforts to satisfy the performance obligation. We allocated the fixed upfront consideration entirely to the Roche License Obligation as the value of the fixed consideration together with the expected value of the remaining development and regulatory milestones, sales-based milestones, and royalties, all of which are either currently constrained at inception or subject to the sales- or usage-based royalty exception, approximates the standalone selling price of the Roche License Obligation. This allocation is consistent with the allocation objective of ASC 606 when considering all of the performance obligations and payment terms in the contract. The Roche License Obligation was satisfied at a point in time upon transfer of the license to Roche. Control of the licenses was transferred on the Effective Date and Roche could begin to use and benefit from the licenses. Because of this, all consideration allocated to the Roche License Obligation, including the upfront payment, milestones and royalties, is recognized when these amounts are no longer considered fully constrained or when the related sales occur for amounts subject to the sales-or-usage based royalty exception of ASC 606. For the Roche Development Services Obligation, we measure proportional performance over time using an input method based on cost incurred relative to the total estimated cost of the obligation, on a quarterly basis, by determining the proportion of effort incurred as a percentage of total effort we expect to expend. This ratio is applied to the transaction price allocated to the obligation. As all costs in the proportional performance model are allowable for reimbursement from Roche, and the assumptions used to determine the total estimated cost of the obligation are consistent with the assumptions used to determine the transaction price allocated to the obligation, the revenue recognized for this obligation will approximate 60 % of the actual reimbursable cost incurred. Management has applied significant judgment in the process of developing our estimates. We re-evaluate the transaction price as of the end of each reporting period and as of December 31, 2025, the total transaction price was determined to be $ 1.74 billion, an increase of $ 423.6 million from December 31, 2024 attributed to the achievement of a $ 300.0 million development milestone due to us upon the first patient dosing in the ZENITH Phase 3 trial in September 2025, as well as a higher probability of success associated with initiation of the Phase 3 trial offset 107 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS by a decrease in the expected costs to perform the development services based on an updated development plan approved by the joint steering committee in September 2025. We recognized $ 300.0 million in net revenue from collaborations as the development milestone specifically relates to the transfer of the license to Roche which occurred on the Effective Date. The following table provides a summary of the transaction price allocated to each performance obligation: (In thousands) As of December 31, 2025 Roche License Obligation $ 675,000 Roche Development Services Obligation 1,061,167 Roche Technology Transfer Obligation 2,000 $ 1,738,167 Net revenues from collaborations recognized under the Roche Agreement consisted of the following: Years Ended December 31, (In thousands) 2025 2024 2023 Roche License Obligation $ 300,000 $ 65,000 $ 310,000 Roche Development Services Obligation 89,002 45,756 23,974 Other 5,879 8,733 3,828 Total $ 394,881 $ 119,489 $ 337,802 As of December 31, 2025, the aggregate amount of the transaction price allocated to the Roche Performance Obligations that was unsatisfied was $ 904.4 million, which is expected to be recognized through the term of the Roche Agreement based on our input method model as the services are performed. We incurred research and development costs related to our collaboration with Roche of $ 160.0 million, $ 92.7 million and $ 44.6 million during the years ended December 31, 2025, 2024 and 2023, respectively. Regeneron Pharmaceuticals, Inc. Overview In 2019, we entered into a global, strategic collaboration with Regeneron Pharmaceuticals, Inc., or Regeneron, to discover, develop and commercialize RNAi therapeutics for a broad range of diseases by addressing therapeutic targets expressed in the eye and central nervous system, or CNS, in addition to a select number of targets expressed in the liver, which we refer to as the Regeneron Collaboration. The Regeneron Collaboration is governed by a Master Agreement, referred to as the Regeneron Master Agreement. In connection with the Regeneron Master Agreement, we and Regeneron entered into (i) a co-co collaboration agreement covering the continued development of cemdisiran, our C5 siRNA, currently in development for C5 complement-mediated diseases, as a monotherapy, or the C5 Co-Co Collaboration Agreement, and (ii) a license agreement to evaluate anti-C5 antibody-siRNA combinations for C5 complement-mediated diseases including evaluating the combination of Regeneron’s pozelimab and cemdisiran, or the C5 License Agreement. The Master Agreement, the C5 Co-Co Collaboration Agreement and the C5 License Agreement were accounted for as a single arrangement because the agreements were negotiated together. In November 2022, Regeneron exercised its right under the C5 Co-Co Collaboration Agreement to opt out of the further development and commercialization of cemdisiran monotherapy. As a result of Regeneron’s decision to opt out, the licenses granted to Regeneron under the C5 Co-Co Collaboration Agreement reverted to us, we had the sole right to continue to develop and commercialize cemdisiran monotherapy, and Regeneron no longer shared in the costs on any monotherapy program. Regeneron remained eligible to receive tiered, double-digit royalties on net sales of cemdisiran as a monotherapy. In June 2024, we entered into an amended and restated C5 License Agreement, or the Amended C5 License Agreement, which terminated the C5 Co-Co Collaboration Agreement and granted Regeneron a worldwide license to cemdisiran as a monotherapy in addition to the license to cemdisiran in combination with anti-C5 antibodies. Through the Amended C5 License Agreement, Regeneron is now solely responsible for development, manufacturing and commercialization of cemdisiran as a monotherapy and in combination with anti-C5 antibodies. As part of the Amended C5 License Agreement, we provided manufacturing technology transfer services for cemdisiran to Regeneron. Regeneron provided us with an upfront payment of $ 10.0 million, and we will receive certain milestone payments upon receipt of regulatory approval for cemdisiran as a monotherapy, and tiered double-digit royalties on net sales. The Amended C5 License Agreement did not change our rights to receive low double-digit royalties and commercial milestones of up to $ 325.0 million on any potential product sales if cemdisiran is used as part of a combination product. 108 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Under the terms of the Regeneron Collaboration, we continue to work exclusively with Regeneron to discover RNAi therapeutics for eye and CNS diseases for an initial research period, which we refer to as the Initial Research Term. The Regeneron Collaboration also covers a select number of RNAi therapeutic programs designed to target genes expressed in the liver. The Initial Research Term will expire in May 2026. As a result, we and Regeneron will not nominate additional targets to be added to our collaboration. Regeneron leads development and commercialization for all programs targeting eye diseases (subject to limited exceptions), entitling us to certain potential milestone and royalty payments pursuant to the terms of a license agreement, the form of which has been agreed upon by the parties. We and Regeneron are alternating leadership on CNS and liver programs, with the lead party retaining global development and commercial responsibility. For such CNS and liver programs, both we and Regeneron have the option at lead candidate selection to enter into a co-co collaboration agreement, the form of which has been agreed upon by the parties, whereby both companies will share equally all costs of, and profits from, all development and commercialization activities under the program. If the non-lead party elects to not enter into a co-co collaboration agreement with respect to a given CNS or liver program, we and Regeneron will enter into a license agreement with respect to such program and the lead party will be the “Licensee” for the purposes of the license agreement. If the lead party for a CNS or liver program elects to not enter into the co-co collaboration agreement, then we and Regeneron will enter into a license agreement with respect to such program and leadership of the program will transfer to the other party and the former non-lead party will be the “Licensee” for the purposes of the license agreement. In connection with the Regeneron Master Agreement, we remain eligible to receive an additional $ 100.0 million milestone payment upon achievement of certain criteria during early clinical development for an eye program. We and Regeneron are continuing to advance programs nominated during the Initial Research Term. For each of these programs, Regeneron will provide us with $ 2.5 million in funding at program initiation and an additional $ 2.5 million at lead candidate identification. For any license agreement subsequently entered into, the licensee will generally be responsible for its own costs and expenses incurred in connection with the development and commercialization of the collaboration products. The licensee will pay to the licensor certain development and/or commercialization milestone payments totaling up to $ 150.0 million for each collaboration product. In addition, following the first commercial sale of the applicable collaboration product under a license agreement, the licensee is required to make certain tiered royalty payments, ranging from low double-digits up to 20 %, to the licensor based on the aggregate annual net sales of the collaboration product, subject to customary reductions. For any co-co collaboration agreement subsequently entered into, we and Regeneron will share equally all costs of, and profits from, development and commercialization activities. Reimbursement of our share of costs will be recognized as a reduction to research and development expense in the consolidated statements of operations and comprehensive income (loss). In the event that a party exercises its opt-out right, the lead party will be responsible for all costs and expenses incurred in connection with the development and commercialization of the collaboration products under the applicable co-co collaboration agreement, subject to continued sharing of costs through defined points. If a party exercises its opt-out right, following the first commercial sale of the applicable collaboration product under a co-co collaboration agreement, the lead party is required to make certain tiered royalty payments, ranging from low double-digits up to 20 %, to the other party based on the aggregate annual net sales of the collaboration product and the timing of the exercise of the opt-out right, subject to customary reductions and a reduction for opt-out transition costs. Contract Modification In June 2024, we determined the Amended C5 License Agreement does not meet the requirements to account for the contract modification as a separate contract under ASC 606 because the consideration exchanged for the additional distinct goods and services does not reflect the standalone selling price. Therefore, we have accounted for the Amended C5 License Agreement and Regeneron Master Agreement as a single combined contract. The modification date was determined to be the June 2024 effective date of the Amended C5 License Agreement. Our performance obligations subsequent to the contract modification included: (i) a research license and research services, collectively referred to as the Research Services Obligation; (ii) a worldwide license to cemdisiran for combination therapies, and manufacturing and development service obligations, collectively referred to as the C5 License Obligation; (iii) a worldwide license to cemdisiran for monotherapies, referred to as the C5 Monotherapy Obligation; and (iv) a technology transfer of the existing manufacturing process for cemdisiran, referred to as the Regeneron Technology Transfer Obligation. The Amended C5 License Agreement did not change the Research Services Obligation or the C5 License Obligation, which were both performance obligations at the inception of our global, strategic collaboration with Regeneron prior to the contract modification. The Amended C5 License Agreement resulted in two additional performance obligations, which were the C5 Monotherapy Obligation and the Regeneron Technology Transfer Obligation. The C5 Monotherapy Obligation was considered functional intellectual property and distinct from other promises as Regeneron can benefit from the cemdisiran monotherapy license on its own or together with other readily available resources and the license is separately identifiable from the other promises in the contract. The Regeneron Technology Transfer Obligation was distinct as Regeneron can benefit from the cemdisiran monotherapy license transferred by us without the technology transfer given cemdisiran was in an advanced 109 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS stage of clinical development and our utilization of third-party contract manufacturing organizations to manufacture cemdisiran. Therefore, the C5 Monotherapy Obligation and the Regeneron Technology Transfer Obligation each represented a separate performance obligation. The initial transaction price of $ 191.5 million allocated to the C5 Monotherapy Obligation was recognized immediately as this obligation was satisfied at a point in time upon transfer of the license to Regeneron. Control of the license was transferred in June 2024 as Regeneron could begin to use and benefit from the license on its own or together with other readily available resources to generate economic benefit from the license. The remaining variable consideration allocated to the C5 Monotherapy Obligation, including milestones and royalties, will be recognized immediately when these amounts are no longer considered fully constrained or when the related sales occur for amounts subject to the sales-or-usage based royalty exception of ASC 606. In the three months ended March 31, 2025, we completed our obligations related to the C5 License Obligation and the Regeneron Technology Transfer Obligation. We continue to perform work in satisfaction of the remaining unsatisfied performance obligation, the Research Services Obligation. For this performance obligation, we measure proportional performance over time using an input method based on cost incurred relative to the total estimated costs for each of the identified obligations by determining the proportion of effort incurred as a percentage of total effort we expect to expend. This ratio is applied to the transaction price allocated to the obligation. Management has applied significant judgment in the process of developing our estimates. Any changes to these estimates will be recognized in the period in which they change as a cumulative catch-up. We re-evaluate the transaction price as of the end of each reporting period and as of December 31, 2025, the total transaction price was determined to be $ 100.5 million related to this obligation. As of December 31, 2025, the aggregate amount of the transaction price that was unsatisfied was $ 34.1 million, which is expected to be recognized through the term of the Regeneron Collaboration based on our input method model as the services are performed. Net revenues from collaborations recognized under the Regeneron Collaboration consisted of the following: Years Ended December 31, (In thousands) 2025 2024 2023 Research Services Obligation $ 39,519 $ 39,097 $ 80,200 C5 License Obligation 21,635 38,341 ( 15,100 ) C5 Monotherapy Obligation — 191,520 — C5 Co-Co Obligation — 700 7,400 Regeneron Technology Transfer Obligation 2,431 — — Other license programs 50,372 33,140 27,968 Total $ 113,957 $ 302,798 $ 100,468 Revenue recognized for the “Other license programs” relates to eight separate programs subject to individual agreements with Regeneron. Deferred revenue is classified as either current or noncurrent in the consolidated balance sheets based on the period the revenue is expected to be recognized. The composition of current deferred revenue related to the Regeneron Collaboration was as follows: As of December 31, (In thousands) 2025 2024 Research Services Obligation $ 4,845 $ 41,156 C5 License Obligation — 12,018 Regeneron Technology Transfer Obligation — 2,307 Total $ 4,845 $ 55,481 We incurred research and development costs related to the Regeneron Collaboration of $ 62.0 million, $ 71.7 million and $ 77.4 million during the years ended December 31, 2025, 2024 and 2023, respectively. Novartis AG In February 2013, we entered into a license and collaboration agreement with The Medicines Company, or MDCO, pursuant to which we granted to MDCO an exclusive, worldwide license to develop, manufacture and commercialize RNAi therapeutics targeting proprotein convertase subtilisin/kexin type 9 for the treatment of hypercholesterolemia and other human diseases, including inclisiran. We refer to this agreement, as amended through the date hereof, as the MDCO License 110 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Agreement. In 2020, Novartis AG, or Novartis, completed its acquisition of MDCO and assumed all of MDCO’s rights and obligations under the MDCO License Agreement. We are entitled to royalties ranging from 10 % up to 20 % based on annual worldwide net sales of licensed products by Novartis, its affiliates and sublicensees, subject to reduction under specified circumstances. Vir Biotechnology, Inc. In March 2025, we and Vir Biotechnology, Inc., or Vir, entered into an amended and restated collaboration and license agreement, or the Amended Vir Agreement, relating to elebsiran (formerly ALN-HBV02 (VIR-2218)). Vir remains solely responsible for development, manufacturing and commercialization of elebsiran. In connection with execution of the Amended Vir Agreement, Vir made a $ 30.0 million payment, and we remain entitled to receive milestone payments upon the achievement of specified regulatory and commercial milestones, and royalties on the net sales of elebsiran ranging from low-to-mid teen percentages. Because the license rights have already been delivered and we have no other remaining performance obligations under the Amended Vir Agreement, the $ 30.0 million payment was recognized within net revenues from collaborations during the year ended December 31, 2025. Other In addition to the collaboration agreements discussed above, we have various other collaboration agreements that are not individually significant to our operating results or financial condition at this time. Pursuant to the terms of those agreements, we may be required to pay, or we may receive, additional amounts contingent upon the occurrence of various future events (e.g., upon the achievement of various development and commercial milestones) which in the aggregate could be significant. We may also incur, or be reimbursed for, significant research and development costs. In addition, if any products related to these collaborations are approved for sale, we may be required to pay, or we may receive, royalties on future sales. The payment or receipt of these amounts, however, is contingent upon the occurrence of various future events. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development and commercialization, it is possible we may not receive any such payments under all of our existing collaboration and license agreements, including the agreements described within this note. 5. FAIR VALUE MEASUREMENTS The following tables present information about our financial assets and liabilities that are measured at fair value on a recurring basis and indicate the fair value hierarchy of the valuation techniques we utilized to determine such fair value: (In thousands) As of December 31, 2025 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets Cash equivalents: Money market funds $ 140,445 $ 140,445 $ — $ — U.S. treasury securities 18,952 — 18,952 — U.S. government-sponsored enterprise securities 2,690 — 2,690 — Commercial paper 1,995 — 1,995 — Marketable debt securities: U.S. treasury securities 653,341 — 653,341 — Corporate notes 333,241 — 333,241 — U.S. government-sponsored enterprise securities 252,634 — 252,634 — Commercial paper 7,017 — 7,017 — Municipal securities 5,001 — 5,001 — Restricted cash (money market funds) 917 917 — — Total financial assets $ 1,416,233 $ 141,362 $ 1,274,871 $ — 111 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (In thousands) As of December 31, 2024 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets Cash equivalents: Money market funds $ 190,779 $ 190,779 $ — $ — U.S. treasury securities 36,428 — 36,428 — Commercial paper 22,709 — 22,709 — U.S. government-sponsored enterprise securities 9,952 — 9,952 — Marketable debt securities: U.S. treasury securities 921,627 — 921,627 — U.S. government-sponsored enterprise securities 396,143 — 396,143 — Corporate notes 361,739 — 361,739 — Commercial paper 35,408 — 35,408 — Municipal securities 5,003 — 5,003 — Marketable equity securities 8,156 8,156 — — Restricted cash (money market funds) 910 910 — — Total financial assets $ 1,988,854 $ 199,845 $ 1,789,009 $ — Financial liabilities Development derivative liability $ 486,919 $ — $ — $ 486,919 For the years ended December 31, 2025 and 2024, there were no transfers between Level 1 and Level 2 financial assets or liabilities. The carrying amounts reflected on our consolidated balance sheets for cash, accounts receivable, net, other current assets, accounts payable and accrued expenses approximate fair value due to their short-term maturities. 6. MARKETABLE DEBT SECURITIES The following tables summarize our marketable debt securities: As of December 31, 2025 (In thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury securities $ 670,566 $ 1,736 $ ( 9 ) $ 672,293 Corporate notes 332,104 1,152 ( 15 ) 333,241 U.S. government-sponsored enterprise securities 254,829 559 ( 64 ) 255,324 Commercial paper 9,012 — — 9,012 Municipal securities 5,000 1 — 5,001 Total $ 1,271,511 $ 3,448 $ ( 88 ) $ 1,274,871 112 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS As of December 31, 2024 (In thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury securities $ 957,145 $ 1,377 $ ( 467 ) $ 958,055 U.S. government-sponsored enterprise securities 405,890 575 ( 370 ) 406,095 Corporate notes 361,311 769 ( 341 ) 361,739 Commercial paper 58,117 — — 58,117 Municipal securities 5,002 1 — 5,003 Total $ 1,787,465 $ 2,722 $ ( 1,178 ) $ 1,789,009 The following table summarizes classification of our marketable debt securities in the consolidated balance sheets: As of December 31, (In thousands) 2025 2024 Cash and cash equivalents $ 23,637 $ 69,089 Marketable debt securities 1,251,234 1,719,920 Total $ 1,274,871 $ 1,789,009 7. OTHER BALANCE SHEET DETAILS Inventory The components of inventory are summarized as follows: As of December 31, (In thousands) 2025 2024 Raw materials $ 14,184 $ 23,965 Work in process 65,122 64,978 Finished goods 32,338 26,433 Total inventory $ 111,644 $ 115,376 As of December 31, 2025 and 2024, we had $ 28.9 million and $ 36.9 million, respectively, of long-term inventory included within other assets in our consolidated balance sheets as we anticipate it being consumed beyond our normal operating cycle. Property, Plant and Equipment, Net Property, plant and equipment, net consisted of the following: As of December 31, (In thousands) 2025 2024 Buildings $ 297,618 $ 294,508 Leasehold improvements 241,077 236,686 Laboratory equipment 140,943 121,957 Manufacturing equipment 48,935 49,062 Computer equipment and software 45,270 42,534 Furniture and fixtures 11,970 11,647 Land 9,080 9,080 Construction in progress 40,954 7,674 835,847 773,148 Less: accumulated depreciation ( 322,700 ) ( 270,364 ) Total property, plant and equipment, net $ 513,147 $ 502,784 113 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Accrued Expenses Accrued expenses consisted of the following: As of December 31, (In thousands) 2025 2024 Product rebates and discounts $ 400,147 $ 361,816 Compensation and related 257,197 214,399 Preclinical, clinical trial and manufacturing 104,097 75,815 Licensing and collaboration agreements 258,856 92,313 Consulting and professional services 34,328 19,974 Other 25,572 29,375 Total accrued expenses $ 1,080,197 $ 793,692 Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within our consolidated balance sheets to the totals of these amounts shown in the consolidated statements of cash flows: As of December 31, (In thousands) 2025 2024 2023 Cash and cash equivalents $ 1,657,250 $ 966,428 $ 812,688 Total restricted cash included in other assets 1,557 2,224 2,196 Total cash, cash equivalents, and restricted cash shown in the consolidated statements of cash flows $ 1,658,807 $ 968,652 $ 814,884 Accumulated Other Comprehensive Loss The following table summarizes the changes in accumulated other comprehensive loss, by component: (In thousands) Loss on Investment in Joint Venture Defined Benefit Pension Plans, Net of Tax Unrealized Gains (Losses) from Debt Securities Foreign Currency Translation Adjustment Total Accumulated Other Comprehensive (Loss) Income Balance as of December 31, 2023 $ ( 32,792 ) $ ( 2,753 ) $ 1,548 $ 10,622 $ ( 23,375 ) Other comprehensive (loss) income before reclassifications — ( 1,613 ) 3 ( 9,643 ) ( 11,253 ) Amounts reclassified from other comprehensive (loss) income — 117 ( 7 ) — 110 Net other comprehensive loss — ( 1,496 ) ( 4 ) ( 9,643 ) ( 11,143 ) Balance as of December 31, 2024 ( 32,792 ) ( 4,249 ) 1,544 979 ( 34,518 ) Other comprehensive income before reclassifications — 531 3,353 11,624 15,508 Amounts reclassified from other comprehensive income — 450 ( 1,537 ) — ( 1,087 ) Net other comprehensive income — 981 1,816 11,624 14,421 Balance as of December 31, 2025 $ ( 32,792 ) $ ( 3,268 ) $ 3,360 $ 12,603 $ ( 20,097 ) Amounts reclassified out of accumulated other comprehensive loss relate to settlements of marketable debt securities and amortization of our pension obligation which are recorded as other income (expense), net in the consolidated statements of operations and comprehensive income (loss). 114 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 8. CONVERTIBLE DEBT AND OTHER FINANCING Convertible Senior Notes Due 2028 On September 8, 2025, we commenced a private offering of $ 575.0 million in aggregate principal amount of 0.00 % convertible senior notes due 2028, or the Initial 2028 Notes. On September 10, 2025, the initial purchasers in such offering exercised their option to purchase an additional $ 86.3 million in aggregate principal amount of our 0.00 % Convertible Senior Notes due 2028, or the Additional 2028 Notes, and together with the Initial 2028 Notes referred to as the 2028 Notes, bringing the total aggregate principal amount of the 2028 Notes issued and outstanding to $ 661.3 million. The 2028 Notes are our senior unsecured obligations. The 2028 Notes were issued pursuant to an indenture, dated September 12, 2025, or the 2025 Indenture, between us and The Bank of New York Mellon, as trustee. The 2025 Indenture includes customary covenants and sets forth certain events of default after which the 2028 Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving us after which the 2028 Notes become automatically due and payable. The 2028 Notes will mature on September 15, 2028, unless earlier converted, redeemed or repurchased. The 2028 Notes will not bear regular interest. Before June 15, 2028, noteholders will have the right to convert their 2028 Notes in certain circumstances and during specified periods: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2025 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130 % of the conversion price on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period in which the trading price per $1,000 principal amount of the 2028 Notes for each trading day of that ten consecutive trading day period was less than 98 % of the product of the last reported sale price of our common stock and the conversion rate on such trading day; (3) if we call any or all of the 2028 Notes for redemption; or (4) upon the occurrence of specified corporate events. From and after June 15, 2028, the 2028 Notes will be convertible at the option of the noteholders at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date. We will settle any conversions of the 2028 Notes by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of common stock, at our election. The conversion rate for the 2028 Notes will initially be 1.4923 shares of common stock per $1,000 principal amount of 2028 Notes, which is equivalent to an initial conversion price of approximately $ 670.11 per share of common stock. The initial conversion price represents a premium of approximately 40 % above the U.S. composite volume weighted average price of our common stock from 12:30 p.m. through 4:00 p.m. Eastern Daylight Time on September 9, 2025, which was $ 478.63 per share. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the 2025 Indenture. We may not redeem the 2028 Notes prior to September 20, 2027. We may redeem for cash all or any portion of the 2028 Notes (subject to certain limitations), at our option, on or after September 20, 2027 and on or prior to the 21st scheduled trading day immediately preceding the maturity date, if the last reported sale price of our common stock has been at least 130 % of the conversion price then in effect for at least 20 trading days (whether or not consecutive), including the trading day immediately preceding the date on which we provide notice of redemption, during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 2028 Notes to be redeemed, plus any accrued and unpaid special interest to, but excluding, the redemption date. No sinking fund is provided for the 2028 Notes, which means that we are not required to redeem or retire the 2028 Notes periodically. If we undergo a fundamental change, which includes certain change of control events or a termination of trading of our common stock, then subject to certain conditions, holders may require us to repurchase for cash all or any portion of their notes at a fundamental change repurchase price equal to 100 % of the principal amount of the 2028 Notes to be repurchased plus accrued and unpaid special interest. In addition, if specific corporate events occur prior to the maturity date or if we issue a notice of redemption, we will increase the conversion rate by pre-defined amounts for holders who elect to convert their notes in connection with such corporate event. The conditions allowing holders of the 2028 Notes to convert were not met as of December 31, 2025. The 2028 Notes were issued at par. As of December 31, 2025, the 2028 Notes were classified as a long-term liability on the consolidated balance sheet and had a carrying value of $ 647.2 million, representing the outstanding principal amount, net of unamortized issuance costs of $ 14.0 million. The issuance costs are amortized to interest expense over the contractual term of the 2028 Notes. As of December 31, 2025, the estimated fair value of the 2028 Notes was approximately $ 637.0 million, which was determined based on the last actively traded price per $100 of the 2028 Notes (Level 2) on that day. As of December 31, 2025, the effective interest rate of the 2028 Notes is 1 %. We used the net proceeds from the issuance of the 2028 Notes to pay the cost of the 2025 Capped Call Transactions, and the remainder of the net proceeds, together with cash on hand, to repay $ 637.8 million aggregate principal amount of the 2027 Notes, as further discussed below. 115 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 2025 Capped Call Transactions In September 2025, in connection with the pricing of the 2028 Notes, we entered into privately negotiated capped call transactions, or 2025 Capped Call Transactions. The 2025 Capped Call Transactions initially cover, subject to customary anti-dilution adjustments, the number of shares of common stock that underlie the 2028 Notes. The initial cap price of the 2025 Capped Call Transactions is $ 837.61 per share, and is subject to certain adjustments under the terms of the 2025 Capped Call Transactions. The 2025 Capped Call Transactions are not part of the terms of the 2028 Notes and are accounted for as separate transactions. As these transactions are indexed to our own stock and are considered equity classified, they are recorded in stockholders’ equity and are not accounted for as derivatives. The cost incurred in connection with the 2025 Capped Call Transactions of $ 35.3 million was recorded as a reduction to additional paid-in capital on our consolidated balance sheet and the fair value of the capped call instrument is not remeasured each reporting period. Convertible Senior Notes Due 2027 On September 12, 2022, we commenced a private offering of $ 900.0 million in aggregate principal amount of 1.00 % Convertible Senior Notes due 2027, or the Initial 2027 Notes. On September 13, 2022, the initial purchasers in such offering exercised their option to purchase an additional $ 135.0 million in aggregate principal amount of our 1.00 % Convertible Senior Notes due 2027, or the Additional 2027 Notes, and together with the Initial 2027 Notes collectively referred to as the 2027 Notes, bringing the total aggregate principal amount of the 2027 Notes issued and outstanding to $ 1.04 billion. The 2027 Notes were issued pursuant to an indenture, dated September 15, 2022, or the 2022 Indenture. The 2022 Indenture includes customary covenants and sets forth certain events of default after which the 2027 Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving us after which the 2027 Notes become automatically due and payable. The 2027 Notes were issued at par. The 2027 Notes will mature on September 15, 2027, unless earlier converted, redeemed or repurchased. The 2027 Notes bear interest at a rate of 1.00 % per year payable semiannually in arrears on March 15 and September 15 of each year, beginning on March 15, 2023. The 2027 Notes are convertible at the option of the noteholder on or after June 15, 2027. Prior to June 15, 2027, the 2027 Notes are convertible only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2022 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130 % of the conversion price on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period in which the trading price per $1,000 principal amount of the 2027 Notes for each trading day of that ten consecutive trading day period was less than 98 % of the product of the last reported sale price of our common stock and the conversion rate of the 2027 Notes on such trading day; (3) if we call any or all of the 2027 Notes for redemption; or (4) upon the occurrence of specific corporate events as set forth in the 2022 Indenture governing the 2027 Notes. We will settle any conversions of the 2027 Notes by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of common stock, at our election. The initial conversion rate for the 2027 Notes is 3.4941 shares of common stock per $1,000 principal amount, which is equivalent to an initial conversion price of approximately $ 286.20 per share of common stock, which represents a premium of approximately 35 % over the last reported sale price of common stock of $ 212.00 per share on September 12, 2022. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the 2022 Indenture. The condition allowing holders of the 2027 Notes to convert was met in the fourth quarter of 2025 due to our common stock trading for at least 20 days during a period of 30 consecutive trading days ending on, and including, the last trading day of the quarter above 130 % of the conversion price, and the 2027 Notes are convertible at the option of the holders in the first quarter of 2026. We are able to redeem the 2027 Notes after September 20, 2025. We may redeem for cash equal to 100 % of the principal amount of the 2027 Notes being redeemed plus accrued and unpaid interest of all or any portion of the 2027 Notes, at our option, on or after September 20, 2025, if the last reported sales price of our common stock has been at least 130 % of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period. As of December 31, 2025, we have not redeemed any of the 2027 Notes under this option. No sinking fund is provided for the 2027 Notes and therefore we are not required to redeem or retire the 2027 Notes periodically. If we undergo a fundamental change, which includes certain change of control events or a termination of trading of our common stock, then subject to certain conditions, holders may require us to repurchase for cash all or any portion of their 2027 Notes at a fundamental change repurchase price equal to 100 % of the principal amount of the 2027 Notes to be repurchased plus accrued and unpaid interest. In addition, if specific corporate events occur prior to the maturity date or if we issue a notice of redemption, we will increase the conversion rate by pre-defined amounts for holders who elect to convert their notes in connection with such corporate event. 116 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS In September 2025, concurrently with the pricing of the 2028 Notes, we entered into privately negotiated transactions with certain holders of the 2027 Notes to repurchase for cash $ 637.8 million aggregate principal amount of the outstanding 2027 Notes for a total repurchase cost (including accrued and unpaid interest of $ 3.1 million) of approximately $ 1.11 billion. The repurchase was accounted for as an induced conversion in accordance with ASU 2024-04. We recorded an inducement expense of $ 39.1 million within loss related to convertible debt in the consolidated statements of operations and comprehensive income (loss) for the year ended December 31, 2025 and a charge to additional paid-in capital of $ 430.4 million within stockholders’ equity. In December 2025, we entered into privately negotiated transactions with certain holders of the 2027 Notes to repurchase for cash $ 34.4 million aggregate principal amount of the outstanding 2027 Notes for a total repurchase cost (including accrued and unpaid interest of $ 0.1 million) of approximately $ 52.3 million. The repurchase was accounted for as an induced conversion in accordance with ASU 2024-04. We recorded an inducement expense of $ 3.3 million within loss related to convertible debt in the consolidated statements of operations and comprehensive income (loss) for the year ended December 31, 2025 and a charge to additional paid-in capital of $ 14.8 million within stockholders’ equity. As of December 31, 2025, we had $ 362.8 million aggregate principal amount of the 2027 Notes outstanding. As of December 31, 2025 and 2024, the 2027 Notes were classified as a long-term liability on the consolidated balance sheets and had a carrying value of $ 360.5 million and $ 1.02 billion, respectively, representing outstanding principal amount net of unamortized issuance costs of $ 2.3 million and $ 10.4 million, respectively. The issuance costs are amortized to interest expense over the contractual term of the 2027 Notes. As of December 31, 2025 and 2024, the estimated fair value of the 2027 Notes was approximately $ 534.1 million and $ 1.11 billion, respectively, which was determined based on the last actively traded price per $100 of the 2027 Notes (Level 2) on the respective dates. As of December 31, 2025 and 2024, the effective interest rate of the 2027 Notes is 1 %. 2022 Capped Call Transactions In 2022, in connection with the pricing of the 2027 Notes, we entered into privately negotiated capped call transactions, or 2022 Capped Call Transactions. The 2022 Capped Call Transactions initially cover, subject to customary anti-dilution adjustments, the number of shares of common stock that underlie the 2027 Notes. The cap price of the 2022 Capped Call Transactions is initially $ 424.00 per share, which represents a premium of 100 % over the last reported sale price of common stock of $ 212.00 per share on September 12, 2022, and is subject to certain adjustments under the terms of the 2022 Capped Call Transactions. As of December 31, 2025, the 2022 Capped Call Transactions remained outstanding. Because these transactions are indexed to our own stock and are considered equity classified, they were recorded in stockholders’ equity and are not accounted for as derivatives. The cost incurred to purchase the 2022 Capped Calls was recorded as a reduction to additional paid-in capital on our consolidated balance sheets and the fair value of the capped call instrument is not remeasured each reporting period. Revolving Credit Agreement On September 30, 2025, we entered into the Revolving Credit Agreement, which provides for a $ 500.0 million revolving line of credit, including a $ 150.0 million sublimit for issuance of letters of credit. The Revolving Credit Agreement matures in September 2030, subject to earlier springing maturity under certain circumstances. Borrowings, if any, will bear interest, at our option, at a base rate plus an applicable margin ranging from 0.50 % to 1.50 % based upon the total leverage ratio or a term Secured Overnight Financing Rate (or an alternative currency term rate) plus an applicable margin ranging from 1.50 % to 2.50 % based upon the total leverage ratio. We are required to pay, on a quarterly basis, a commitment fee ranging between 0.20 % to 0.35 % (depending on our total leverage ratio) of unused available commitments under the Revolving Credit Agreement. We are also obligated to pay the administrative agent fees customary for revolving credit facilities of this size and type. The Revolving Credit Agreement contains customary affirmative and negative covenants and conditions to borrowing, as well as customary events of default. In addition, the Revolving Credit Agreement contains financial covenants that require us to maintain a total leverage ratio less than or equal to 3.75 :1.00 and an interest coverage ratio greater than or equal to 3.00 :1.00, each tested at the end of each fiscal quarter. As of December 31, 2025, we were in compliance with the financial covenants. As of December 31, 2025, we had no borrowings and $ 17.5 million of letters of credit outstanding under the Revolving Credit Agreement. 9. LIABILITIES RELATED TO THE SALE OF FUTURE ROYALTIES AND DEVELOPMENT FUNDING Development Funding Liabilities In August 2020, we entered into a co-development agreement, referred to as the Development Funding Agreement, with BXLS V Bodyguard – PCP L.P. and BXLS Family Investment Partnership V – ESC L.P., collectively referred to as Blackstone Life Sciences, pursuant to which Blackstone Life Sciences will provide up to $ 150.0 million in funding for the clinical 117 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS development of vutrisiran and zilebesiran, two of our cardiometabolic programs. As of December 31, 2025, Blackstone Life Sciences has provided $ 70.0 million to fund vutrisiran development costs related to the HELIOS-B Phase 3 clinical trial and $ 26.0 million to fund Phase 2 clinical trials of zilebesiran. Additionally, Blackstone Life Sciences is obligated to fund $ 18.0 million for the Phase 3 clinical trial of zilebesiran following a development milestone triggered in September 2025, of which $ 6.0 million has been provided as of December 31, 2025. The amount of funding ultimately provided by Blackstone Life Sciences for the Phase 3 clinical trial of zilebesiran is dependent on us achieving the remaining specified development milestones. As agreed between Blackstone Life Sciences and the Company, we retain sole responsibility for the development and commercialization of both vutrisiran and zilebesiran. As consideration for Blackstone Life Sciences’ funding for vutrisiran clinical development costs, we agreed to pay Blackstone Life Sciences $ 175.0 million triggered upon obtaining regulatory approval of vutrisiran for ATTR amyloidosis with cardiomyopathy, or ATTR-CM, and a 1 % royalty on net sales of vutrisiran for a 10-year term beginning upon the first commercial sale following regulatory approval of vutrisiran for ATTR-CM. In March 2025, we obtained a regulatory approval from the FDA for vutrisiran for ATTR-CM, triggering the $ 175.0 million payable to Blackstone Life Sciences in eight equal quarterly payments over two years . In September 2023, we announced positive topline results from the KARDIA-1 Phase 2 clinical trial of zilebesiran, triggering the achievement of the development milestone of $ 84.5 million payable to Blackstone Life Sciences in 16 equal quarterly payments over four years , as consideration for Blackstone Life Sciences’ funding for Phase 2 clinical development costs of zilebesiran. As consideration for funding for Phase 3 clinical development costs of zilebesiran, we agreed to pay Blackstone Life Sciences $ 243.0 million in 16 equal quarterly payments over four years triggered upon regulatory approval of zilebesiran in specified countries, unless it is later withdrawn from the market following a mandatory recall. Our payment obligations under the Development Funding Agreement are secured, subject to certain exceptions, by security interests in intellectual property owned by us relating to vutrisiran and zilebesiran, as well as in our bank account in which the funding deposits will be made. We and Blackstone Life Sciences each have the right to terminate the Development Funding Agreement in its entirety in the event of the other party’s bankruptcy or similar proceedings. We and Blackstone Life Sciences may each terminate the Development Funding Agreement in its entirety or with respect to either product in the event of an uncured material breach by the other party, or with respect to a product for certain patient health and safety reasons, or if regulatory approval in specified major market countries is not obtained for the product following the completion of clinical trials for the product. In addition, Blackstone Life Sciences has the right to terminate the Development Funding Agreement in its entirety upon the occurrence of certain events affecting our ability to make payments under the agreement or to develop or commercialize the products, or upon a change of control of us. Blackstone Life Sciences may also terminate the Development Funding Agreement with respect to a product if the joint steering committee elects to terminate the development program for that product in its entirety, if certain clinical endpoints are not achieved for that product or, with respect to vutrisiran only, if our right to develop or commercialize vutrisiran is enjoined in a specified major market as a result of an alleged patent infringement. In certain termination circumstances, we will be obligated to pay Blackstone Life Sciences an amount that is equal to, or a multiplier of, the development funding received from Blackstone Life Sciences, and we may remain obligated under certain circumstances to make the payments to Blackstone Life Sciences described above should we obtain regulatory approval for zilebesiran following termination. We previously accounted for the Development Funding Agreement under ASC 815 as a derivative liability measured at fair value because it did not meet any of the derivative scope exceptions. In the fourth quarter of 2025, we adopted ASU 2025-07 on a modified retrospective basis as of January 1, 2025, which codified a new scope exception to the guidance of ASC 815. Refer to Note 2, Summary of Significant Accounting Policies, for further information related to the impact of adoption. We determined the underlyings in the Development Funding Agreement now qualify for this new scope exception and, as a result, are no longer accounted for under ASC 815. Beginning on the date of adoption of ASU 2025-07, or January 1, 2025, we record the proceeds received from Blackstone Life Sciences as debt obligations, net of closing costs, on our consolidated balance sheet due to our continuing involvement and obligation to repay Blackstone Life Sciences. We recognized $ 271.5 million as a cumulative effect adjustment to accumulated deficit as of January 1, 2025 as a result of the removal of the development derivative liability and establishment of new debt obligations. The debt obligations to repay Blackstone Life Sciences for the vutrisiran and zilebesiran funding are accreted from the initial carrying amount to the total payment amount using the effective interest rate method over the life of the Development Funding Agreement. The effective interest rate is determined based on the proceeds received and projections of the amounts and timing of the future cash flows. The accretion is recorded as interest expense in the consolidated statement of operations and comprehensive income (loss). We recognize the proceeds received and the principal portion of payments made to Blackstone Life Sciences as financing activities within the consolidated statement of cash flows. As of December 31, 2025, our estimate of total interest expense resulted in an effective annual interest rate of 46 % related to vutrisiran and 32 % related to zilebesiran. 118 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS As payments are made to Blackstone Life Sciences, the balance of the liabilities is effectively repaid over the life of the Development Funding Agreement. The exact timing and amount of repayment is likely to change each reporting period. A significant increase or decrease in vutrisiran global net product revenues will materially impact the liability related to the vutrisiran payments and interest expense recognized. At each balance sheet date, we assess the expected payments to Blackstone Life Sciences and we prospectively adjust the amortization of the liabilities and the related interest expense. The following table shows the activity with respect to the vutrisiran development funding liability, in thousands: Carrying value as of January 1, 2025 $ 190,123 Interest expense 81,737 Amount paid ( 77,707 ) Carrying value as of December 31, 2025 $ 194,153 As of December 31, 2025, we recorded $ 94.5 million within liabilities related to the sale of future royalties and development funding and $ 99.7 million within liabilities related to the sale of future royalties and development funding, net of current portion on our consolidated balance sheet related to the vutrisiran development funding liability. The following table shows the activity with respect to the zilebesiran development funding liability, in thousands: Carrying value as of January 1, 2025 $ 25,319 Interest expense 6,853 Amount paid ( 21,125 ) Amount received 6,000 Carrying value as of December 31, 2025 $ 17,047 As of December 31, 2025, we recorded $ 6.8 million within liabilities related to the sale of future royalties and development funding and $ 10.3 million within liabilities related to the sale of future royalties and development funding, net of current portion on our consolidated balance sheet related to the zilebesiran development funding liability. The fair values of the vutrisiran and zilebesiran development funding liabilities were $ 541.3 million and $ 116.2 million, respectively, as of December 31, 2025, based on our current estimates of future payments over the life of the arrangements and an estimated market participant weighted average cost of capital, which are considered Level 3 inputs. As of December 31, 2024, the zilebesiran and vutrisiran funding obligations were accounted for as a derivative liability. We recorded $ 93.8 million within development derivative liability and $ 393.1 million within development derivative liability, net of current portion on our consolidated balance sheet. The change in fair value due to the remeasurement of the development derivative liability was recorded within other income (expense), net on our consolidated statements of operations and comprehensive income (loss) for the years ended December 31, 2024 and 2023. As of December 31, 2024, the development derivative liability was classified as a Level 3 financial liability in the fair value hierarchy. The valuation method incorporated certain unobservable Level 3 key inputs including (i) the probability and timing of achieving stated development milestones to receive payments from Blackstone Life Sciences, (ii) the probability and timing of achieving regulatory approval and payments to Blackstone Life Sciences, (iii) an estimate of the amount and timing of the royalty payable on net sales of vutrisiran, assuming regulatory approval for ATTR-CM, (iv) our cost of borrowing ( 10 %), and (v) Blackstone Life Sciences’ cost of borrowing ( 7 %). The following table presents the activity with respect to the development derivative liability, in thousands: Carrying value as of December 31, 2023 $ 324,941 Amount received under the Development Funding Agreement 12,333 Amount paid under the Development Funding Agreement ( 21,125 ) Loss recorded from change in fair value 170,770 Carrying value as of December 31, 2024 $ 486,919 Liability Related to the Sale of Future Royalties In April 2020, we entered into a purchase and sale agreement, or Purchase Agreement, with BX Bodyguard Royalties L.P. (an affiliate of The Blackstone Group Inc.), or Blackstone Royalties, pursuant to which Blackstone Royalties acquired a 119 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS percentage of royalties payable, or the Royalty Interest, initially set at 50 % with respect to net sales by MDCO, its affiliates or sublicensees of inclisiran (or the branded drug product, Leqvio) and any other licensed products under the MDCO License Agreement, and 75 % of the commercial milestone payments payable under the MDCO License Agreement, together with the Royalty Interest, the Purchased Interest. If Blackstone Royalties does not receive payments in respect to the Royalty Interest by December 31, 2029, equaling at least $ 1.00 billion, Blackstone Royalties will receive the Royalty Interest at 55 % beginning on January 1, 2030. In consideration for the sale of the Purchased Interest, Blackstone Royalties paid us $ 1.00 billion. Due to our continuing involvement and an obligation to repay Blackstone Royalties, we recorded the proceeds from this transaction as a debt, net of closing costs, on our consolidated balance sheets. The debt obligations to repay the Purchased Interest are accreted from the initial carrying amount to the total payment amount using the effective interest rate method over the life of the Purchase Agreement. The effective interest rate is determined based on the proceeds received and projections of the amounts and timing of the future cash flows. The accretion is recorded as interest expense in the consolidated statements of operations and comprehensive income (loss). As of December 31, 2025 and 2024, our estimate of this total interest expense resulted in an effective annual interest rate of 10 % and 10 %, respectively. These estimates contain assumptions that impact both the amount recorded at execution and the interest expense that will be recognized in future periods. We account for any royalties and commercial milestones due to us under the MDCO License Agreement as revenue on our consolidated statements of operations and comprehensive income (loss). As payments are made to Blackstone Royalties, the balance of the liability is effectively repaid over the life of the Purchase Agreement. The exact timing and amount of repayment is likely to change each reporting period. A significant increase or decrease in Leqvio global net revenue will materially impact the liability, interest expense and the time period for repayment. At each balance sheet date, we assess the expected payments to Blackstone Royalties and we prospectively adjust the amortization of the liability and the related interest expense. As of December 31, 2025 and 2024, the carrying value of the liability was $ 1.48 billion and $ 1.45 billion, net of closing costs of $ 8.3 million and $ 9.1 million, respectively. The carrying value of the liability approximates fair value as of December 31, 2025 and is based on our current estimates of future royalties expected to be paid to Blackstone Royalties over the life of the arrangement, which is considered a Level 3 input. The following table shows the activity with respect to the liability, in thousands: Carrying value as of December 31, 2023 $ 1,377,239 Interest expense 127,133 Payments ( 57,001 ) Carrying value as of December 31, 2024 1,447,371 Interest expense 149,809 Payments ( 117,971 ) Carrying value as of December 31, 2025 $ 1,479,209 As of December 31, 2025 and 2024, we recorded $ 118.8 million and $ 112.1 million, respectively, within liabilities related to the sale of future royalties and development funding and $ 1.36 billion and $ 1.34 billion, respectively, within liabilities related to the sale of future royalties and development funding, net of current portion related to the Purchased Interest. 10. STOCKHOLDERS' EQUITY (DEFICIT) Stock-Based Compensation The following table summarizes stock-based compensation expenses included in operating costs and expenses: Years Ended December 31, (In thousands) 2025 2024 2023 Research and development $ 153,395 $ 127,749 $ 97,273 Selling, general and administrative 194,840 144,335 124,407 Total $ 348,235 $ 272,084 $ 221,680 120 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS The following table summarizes stock-based compensation expense by type of award: Years Ended December 31, (In thousands) 2025 2024 2023 Time-based restricted stock units $ 164,785 $ 108,501 $ 55,169 Performance-based restricted stock units 121,449 73,295 63,879 Time-based stock options 56,477 85,467 99,165 Other equity programs 10,034 8,054 7,652 Less: Stock-based compensation expense capitalized to inventory ( 4,510 ) ( 3,233 ) ( 4,185 ) Total $ 348,235 $ 272,084 $ 221,680 The following table summarizes our unrecognized stock-based compensation expense, net of estimated forfeitures, by type of awards, and the weighted-average period over which that expense is expected to be recognized: As of December 31, 2025 Unrecognized Expense, Net of Estimated Forfeitures (in thousands) Weighted-average Recognition Period (in years) Time-based restricted stock units $ 221,963 1.54 Performance-based restricted stock units * $ 59,409 2.13 Time-based stock options $ 39,276 1.71 Other equity programs $ 3,957 0.53 __________________________________________ * Excludes performance-based restricted stock units for which the associated vesting events are not yet determined to be probable. Time-Based Restricted Stock Units and Awards The following table summarizes the activity of our time-based restricted stock units and awards, excluding performance-based restricted stock units: Number of Units (in thousands) Weighted-average Grant Date Fair Value (per share) Outstanding as of December 31, 2024 1,725 $ 175.39 Awarded 894 $ 266.05 Released ( 702 ) $ 177.13 Cancelled ( 181 ) $ 194.93 Outstanding as of December 31, 2025 1,736 $ 219.38 Performance-Based Restricted Stock Units The following table summarizes the activity of our performance-based restricted stock units: Number of Units (in thousands) Weighted-average Grant Date Fair Value (per share) Outstanding as of December 31, 2024 954 $ 156.56 Awarded 396 $ 243.53 Released ( 451 ) $ 157.31 Cancelled ( 120 ) $ 183.73 Outstanding as of December 31, 2025 779 $ 197.48 121 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Certain performance-based restricted stock units will vest upon the three-year anniversary of the date of grant, with the number of shares vested dependent on the assessed level of achievement of specific clinical development, regulatory, commercial and/or financial performance events, as approved by our people, culture and compensation committee. Certain performance-based restricted stock units will vest upon the later of the one-year anniversary of the date of grant and the achievement of specific clinical development, regulatory, commercial and/or financial performance events, as approved by our people, culture and compensation committee, with the number of shares vested established on the grant date. Time-Based Stock Options The following table summarizes the activity of our time-based stock options, excluding performance-based stock options: Number of Options (in thousands) Weighted-average Exercise Price (per share) Weighted-average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2024 4,863 $ 133.80 Granted 288 $ 248.08 Exercised ( 1,683 ) $ 128.58 Cancelled ( 101 ) $ 183.51 Outstanding as of December 31, 2025 3,367 $ 144.73 5.38 $ 850,730 Exercisable as of December 31, 2025 2,744 $ 132.29 4.80 $ 728,074 Vested or expected to vest as of December 31, 2025 3,320 $ 143.93 5.35 $ 842,655 The weighted-average fair value of stock options granted was $ 124.07 , $ 79.39 and $ 96.53 per share for the years ended December 31, 2025, 2024 and 2023, respectively. The intrinsic value of stock options exercised was $ 366.3 million, $ 273.2 million and $ 107.0 million for the years ended December 31, 2025, 2024 and 2023, respectively. We satisfy stock option exercises with newly issued shares of our common stock. Performance-Based Stock Options The following table summarizes the activity of our performance-based stock options granted under our equity plans: Number of Options (in thousands) Weighted-average Exercise Price (per share) Weighted-average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2024 273 $ 99.24 Exercised ( 153 ) $ 99.08 Outstanding as of December 31, 2025 120 $ 99.44 1.83 $ 35,737 Exercisable as of December 31, 2025 120 $ 99.44 1.83 $ 35,737 The intrinsic value of performance-based stock options exercised was $ 37.1 million, $ 22.5 million and $ 9.7 million for the years ended December 31, 2025, 2024 and 2023, respectively. We satisfy performance-based stock option exercises with newly issued shares of our common stock. Valuation Assumptions for Stock Options The grant-date fair value of stock options was estimated using the Black-Scholes option-pricing model. Our expected stock-price volatility assumption is based on the historical volatility of our publicly traded stock. The expected life assumption is based on our historical data. The dividend yield assumption is based on the fact that we have never paid cash dividends and have no present intention to pay cash dividends. The risk-free rate for periods within the expected option life is based on the U.S. Treasury yield curve in effect at the time of grant. 122 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS The following table summarizes the Black-Scholes valuation assumption inputs for employee stock options granted: Years Ended December 31, 2025 2024 2023 Risk-free interest rate 4.0 - 4.1 % 4.2 - 4.3 % 3.5 - 4.1 % Expected dividend yield — — — Expected option life 5.9 years 6.0 years 5.1 - 7.0 years Expected volatility 46 - 47 % 47 - 48 % 49 - 60 % Stock Plans In May 2025, our stockholders approved the second amendment and restatement of our 2018 Stock Incentive Plan, or, the Second Amended and Restated 2018 Plan, which increased the number of shares authorized for issuance thereunder by 7,000,000 shares. The Second Amended and Restated 2018 Plan provides for the granting of stock options, restricted stock and restricted stock units (together, restricted stock awards), stock appreciation rights and other stock-based awards, and has a fungible share pool. Any award that is not a full value award is counted against the authorized share limits specified as one share for each share of common stock subject to the award, and all full value awards, defined as restricted stock awards or other stock-based awards, are counted as one and a half shares for each one share of common stock subject to such full value award. As of December 31, 2025, an aggregate of 16,891,503 shares of common stock were reserved for issuance under our stock plans, including outstanding stock options to purchase 3,487,323 shares of common stock, 2,515,120 outstanding restricted stock units, 10,514,222 shares of common stock available for additional equity awards and 374,838 shares of common stock available for future grant under our Amended and Restated 2004 Employee Stock Purchase Plan, as amended, or the Amended and Restated ESPP. Each stock option shall expire within 10 years of grant date. Time-based stock options granted to employees generally vest as to 25 % of the shares on the first anniversary of the grant date and 6.25 % of the shares at the end of each successive three-month period thereafter until fully vested. Restricted stock units granted to employees generally vest over a three-year period, with one-third of the shares vesting on each of the three successive anniversaries of the grant date. Vesting may be accelerated in certain circumstances, including upon death, disability, retirement or termination without cause in connection with a change of control. Employee Stock Purchase Plan In 2004, we adopted the 2004 Employee Stock Purchase Plan and in 2017, our stockholders approved the Amended and Restated ESPP. In 2020, our stockholders approved an amendment to the Amended and Restated ESPP, to increase the number of shares authorized for issuance to 1,965,789 shares. Under the Amended and Restated ESPP, as amended, each offering period is six months , at the end of which employees may purchase shares of common stock through payroll deductions made over the term of the offering. The per-share purchase price at the end of each offering period is equal to the lesser of 85 % of the closing price of our common stock at the beginning or end of the offering period. We issued 92,868 and 140,161 shares during the years ended December 31, 2025 and 2024, respectively. We estimate the fair value of shares to be issued under the Amended and Restated ESPP, as amended, using the Black-Scholes option-pricing model on the date of grant, or first day of the offering period. The following table summarizes the Black-Scholes valuation assumption inputs for stock purchase rights granted under the employee stock purchase plan: Years Ended December 31, 2025 2024 2023 Risk-free interest rate 3.8 % - 4.2 % 4.4 % - 5.4 % 5.1 % - 5.4 % Expected dividend yield — — — Expected option life 6 months 6 months 6 months Expected volatility 38 % - 48 % 35 % - 54 % 34 % - 39 % Preferred Stock We have authorized up to 5,000,000 shares of preferred stock, $ 0.01 par value per share, for issuance. The preferred stock will have such rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, as shall be determined by our board of directors upon its issuance. As of December 31, 2025 and 2024, there were no shares of preferred stock outstanding. 123 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 11. NET INCOME (LOSS) PER COMMON SHARE We compute basic net income (loss) per common share by dividing net income (loss) by the weighted-average number of common shares outstanding. Diluted net income per common share utilizing the treasury stock and if-converted methods is based upon the weighted-average number of common shares and dilutive potential common share equivalents outstanding during the period. For periods in which we have generated a net loss, diluted net loss per common share is the same as basic net loss per common share, as the inclusion of potentially dilutive common shares would be anti-dilutive. The following table sets forth the computation of basic and diluted net income (loss) per share: Years Ended December 31, (In thousands, except per share amounts) 2025 2024 2023 Net income (loss), as reported $ 313,747 $ ( 278,157 ) $ ( 440,242 ) Adjustment for the elimination of interest expense on the convertible debt — — — Net income (loss), for use in diluted income per share $ 313,747 $ ( 278,157 ) $ ( 440,242 ) Weighted-average common shares — basic 131,004 127,651 124,906 Effect of dilutive securities: Options to purchase common stock, inclusive of performance-based stock options 2,265 — — Restricted stock units, inclusive of performance-based restricted stock units 1,407 — — Employee stock purchase program 8 — — Weighted-average common shares — diluted 134,684 127,651 124,906 Net income (loss) per common share — basic $ 2.39 $ ( 2.18 ) $ ( 3.52 ) Net income (loss) per common share — diluted $ 2.33 $ ( 2.18 ) $ ( 3.52 ) The following table sets forth the potential common shares excluded from the calculation of diluted net loss per common share because their inclusion would be anti-dilutive: Years Ended December 31, (In thousands) 2025 2024 2023 Options to purchase common stock, inclusive of performance-based stock options 118 5,136 7,422 Restricted stock units, inclusive of performance-based restricted stock units 7 2,679 2,058 Convertible debt 3,238 3,616 3,616 Total 3,363 11,431 13,096 The effect of the 2022 Capped Call Transactions and 2025 Capped Call Transactions was also excluded from the calculation of diluted net income (loss) per share because exercise of these transactions would potentially reduce the number of shares of our common stock outstanding and, therefore, would be anti-dilutive. In the years ended December 31, 2025 and 2024, we excluded 6.2 million and 5.2 million shares, respectively, related to these transactions. 12. LEASES Overview of Significant Leases We lease two facilities for office and laboratory space in Cambridge, Massachusetts that represent substantially all of our significant lease obligations. An overview of these significant leases is as follows: 675 West Kendall Street We lease office and laboratory space located at 675 West Kendall Street, Cambridge, Massachusetts for our corporate headquarters from BMR-675 West Kendall Street, LLC under a non-cancelable real property lease. The lease commenced on May 1, 2018 and monthly rent payments became due commencing on February 1, 2019 upon substantial completion of the building improvements, and continue for 15 years, with options to renew for two five-year terms each. We are not reasonably 124 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS certain to exercise these options, therefore, the periods covered by the options were not included in the lease term as of December 31, 2025 or 2024. 300 Third Street We lease office and laboratory space located at 300 Third Street, Cambridge, Massachusetts under a non-cancelable real property lease agreement by and between us and ARE-MA Region No. 28, LLC, or ARE-MA, dated as of September 26, 2003, as amended. The term of the lease expires on January 31, 2034 with options to renew for two five-year terms each. We are not reasonably certain to exercise these options, therefore, the periods covered by the options were not included in the lease term as of December 31, 2025 or 2024. Other Lease Disclosures Our facility leases described above generally contain customary provisions allowing the landlords to terminate the leases if we fail to remedy a breach of any of our obligations under any such lease within specified time periods, or upon our bankruptcy or insolvency. The following table is a summary of the components of total lease cost for the years ended December 31, 2025, 2024, and 2023: Years Ended December 31, (In thousands) 2025 2024 2023 Operating lease cost $ 49,816 $ 45,986 $ 46,367 Variable lease cost 24,551 19,757 20,278 Total $ 74,367 $ 65,743 $ 66,645 Our variable lease cost for the years ended December 31, 2025, 2024 and 2023 primarily related to operating expenses, taxes and insurance associated with our real estate leases. Short-term lease costs were not material for the years ended December 31, 2025, 2024 and 2023. Net cash paid for the amounts included in the measurement of the operating lease liabilities in our consolidated balance sheets and presented within operating activities in our consolidated statements of cash flows was $ 50.7 million, $ 51.0 million and $ 46.5 million for the years ended December 31, 2025, 2024 and 2023, respectively. The weighted-average remaining lease term and weighted-average discount rate for all leases as of December 31, 2025 was 8 years and 8 %, respectively, and as of December 31, 2024 was 8 years and 8 %, respectively. Future lease payments for non-cancellable operating leases and a reconciliation to the carrying amount of the operating lease liabilities presented in the consolidated balance sheet as of December 31, 2025 were as follows, in thousands: Years Ending December 31 2026 $ 48,073 2027 52,747 2028 44,308 2029 42,990 2030 41,783 2031 and thereafter 136,375 Total undiscounted lease liability 366,276 Less imputed interest ( 95,671 ) Total discounted lease liability $ 270,605 Operating lease liabilities $ 45,518 Operating lease liabilities, net of current portion 225,087 Total $ 270,605 125 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 13. COMMITMENTS AND CONTINGENCIES Technology License and Other Commitments We have licensed from third parties the rights to use certain technologies and information in our research processes as well as in any other products we may develop. In accordance with the related license or technology agreements, we are required to make certain fixed payments to the licensor or a designee of the licensor over various agreement terms. Many of these agreement terms are consistent with the remaining lives of the underlying intellectual property that we have licensed. As of December 31, 2025, our commitments over the next five years to make fixed and cancellable payments under existing license agreements were not material. Legal Matters From time to time, we may be a party to litigation, arbitration or other legal proceedings in the ordinary course of our business activities, including the following types of matters which are common to companies in our industry: • Patent litigation, which typically involves challenges to the coverage and/or validity of patents on various products or product candidates, processes or dosage forms. An adverse outcome could result in loss of patent protection for a product or product candidates, a significant loss of revenues from a product or impairment of the value of associated assets. • Product liability and other product-related litigation related to our products, which could include personal injury, consumer fraud, off-label promotion, securities, antitrust and breach of contract claims, among others, and often involves highly complex issues relating to medical causation, label warnings and reliance on those warnings, scientific evidence and findings, actual, provable injury and other matters. • Commercial and other asserted or unasserted matters, which can include acquisition-, licensing-, intellectual property-, collaboration- or co-promotion-related and product-pricing claims and environmental claims and proceedings, which can involve complexities that will vary from matter to matter. • Government investigations, which often are related to the extensive regulation of pharmaceutical companies by national, state and local government agencies in the U.S. and in other jurisdictions. The outcome of any such legal proceedings, regardless of the merits, is inherently uncertain. In addition, litigation and related matters are costly and may divert the attention of our management and other resources that would otherwise be engaged in other activities. If we were unable to prevail in any such legal proceedings, it could have a materially adverse effect on our business, results of operations, liquidity and financial condition. If we determine that it is probable that future expenditures will be made for a particular matter and such expenditures can be reasonably estimated, we accrue a loss contingency based on our best estimate of the probable range of loss. We accrue the minimum amount within the probable range of loss if no amount within the range is more likely than another. If we determine that future expenditures are not probable, or probable but not reasonably estimated, we do not accrue a loss contingency. If we determine that a material loss is reasonably possible and the range of loss can be estimated, we disclose the possible range of loss. On a quarterly basis, we evaluate developments with these claims and legal proceedings that could result in a loss contingency accrual, or an increase or decrease to a previously accrued loss contingency. There were no material loss contingencies accrued as of December 31, 2025 or 2024. Patent Litigations In March 2022, we filed separate lawsuits in the U.S. District Court for the District of Delaware, or the District Court, against (1) Moderna, Inc. and its subsidiaries ModernaTX, Inc. and Moderna US, Inc., collectively referred to as Moderna, which we refer to as the Moderna lawsuit, and (2) Pfizer, Inc. and its subsidiary Pharmacia & Upjohn Co. LLC, collectively referred to as Pfizer, which we refer to as the Pfizer lawsuit, seeking damages for patent infringement in Moderna’s and Pfizer’s manufacture and sale of their messenger RNA COVID-19 vaccines. In May 2022, Pfizer added BioNTech SE to the Pfizer lawsuit. In August 2025, we and Moderna settled all claims between the parties in the Moderna lawsuit, and in September 2025, we and Pfizer settled all claims between the parties in the Pfizer lawsuit. On July 12, 2024, Acuitas Therapeutics, Inc., or Acuitas, filed a declaratory judgment action against us in the District Court, seeking a judgment adding certain Acuitas employees as co-inventors on the patents we have asserted against Pfizer/BioNTech and Moderna in our lawsuits. On September 19, 2024, we filed a motion to dismiss, arguing Acuitas did not have standing to sue and failed to state a claim upon which relief could be granted. On July 1, 2025, the District Court granted our motion to dismiss the complaint without prejudice, finding that the plaintiffs had failed to plead facts sufficient to establish standing. On December 12, 2024, The Board of Regents of the University of Texas System filed a lawsuit in the U.S. District Court for the Western District of Texas, or the Texas District Court, alleging that we infringe U.S. Patent No. 8,895,717 by making, using and commercializing ONPATTRO in the U.S. On February 5, 2025, we filed a motion to dismiss the case for improper 126 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS venue and an alternative motion to transfer the case to the U.S. District Court for the District of Massachusetts if the dismissal is not granted. On July 2, 2025, the Texas District Court denied the motion to dismiss and to transfer the case without prejudice, and we filed a renewed motion to dismiss and to transfer the case on September 24, 2025. On December 15, 2025, the court granted in part and denied in part our motion to dismiss and ordered the case transferred to the U.S. District Court for the District of Massachusetts after determining that venue was improper in the Western District of Texas. Government Investigation In October 2025, we received a subpoena from the U.S. Attorney’s Office for the District of Massachusetts seeking documents pertaining to our government price reporting for AMVUTTRA, ONPATTRO, OXLUMO and GIVLAARI, including certain fee and discount arrangements with distributors, and certain other related documents and communications. We are producing records responsive to the subpoena. Indemnification Obligations In connection with license agreements we may enter with companies to obtain rights to intellectual property, we may be required to indemnify such companies for certain damages arising in connection with the intellectual property rights licensed under the agreements. Under such agreements, we may be responsible for paying the costs of any litigation relating to the license agreements or the underlying intellectual property rights, including the costs associated with certain litigation regarding the licensed intellectual property. We are also a party to a number of agreements entered into in the ordinary course of business, which contain typical provisions that obligate us to indemnify the other parties to such agreements upon the occurrence of certain events, including litigation or other legal proceedings. In addition, we have agreed to indemnify our officers and directors for expenses, judgments, fines, penalties, excise taxes, and settlement amounts paid in connection with any threatened, pending or completed litigation proceedings, in which an officer or director was, is or will be involved as a party, on account of such person’s status as an officer or director, or by reason of any action taken by the officer or director while acting in such capacity, subject to certain limitations. These indemnification costs are charged to selling, general and administrative expense. Our maximum potential future liability under any such indemnification provisions is uncertain. We have reviewed the estimated aggregate fair value of our potential liabilities under all such indemnification provisions and have not recorded any related liability as of December 31, 2025 or 2024. 14. INCOME TAXES The domestic and foreign components of income (loss) before income taxes were as follows: Years Ended December 31, (In thousands) 2025 2024 2023 Domestic $ 18,300 $ ( 571,926 ) $ ( 450,311 ) Foreign 304,852 194,551 16,794 Income (loss) before income taxes $ 323,152 $ ( 377,375 ) $ ( 433,517 ) During the year ended December 31, 2025, our foreign income of $ 304.9 million primarily relates to income generated in Switzerland. The (provision for) benefit from income taxes consisted of the following: Years Ended December 31, (In thousands) 2025 2024 2023 Current provision: State $ ( 1,934 ) $ ( 1,600 ) $ ( 4,022 ) Foreign ( 9,669 ) ( 5,944 ) ( 3,416 ) Total current provision ( 11,603 ) ( 7,544 ) ( 7,438 ) Deferred benefit: Foreign 2,198 106,762 713 Total deferred benefit 2,198 106,762 713 Total (provision for) benefit from income taxes $ ( 9,405 ) $ 99,218 $ ( 6,725 ) During the year ended December 31, 2025, we recorded a provision for income taxes of $ 9.4 million. This is comprised of $ 2.2 million of foreign deferred benefit, $ 1.9 million of domestic state current provision and $ 9.7 million of foreign current provision. 127 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS As further described in Note 2, Summary of Significant Accounting Policies, we have elected to prospectively adopt the guidance in ASU 2023-09. The following table is a reconciliation of our effective income tax rate to the statutory federal income tax rate for the year ended December 31, 2025 in accordance with the guidance in ASU 2023-09: (In thousands) Year Ended December 31, 2025 Rate Amount At U.S. federal statutory rate 21.0 % $ ( 67,861 ) State taxes, net of federal effect (1) ( 0.7 ) 2,103 Foreign tax effects Switzerland Statutory tax rate difference between Switzerland and United States ( 11.1 ) 35,749 Statutory permanent item ( 1.5 ) 4,932 Favorable tax ruling ( 6.4 ) 20,576 Canton taxes, Zug ( 0.1 ) 457 Other foreign jurisdictions 1.2 ( 3,706 ) Effect of cross-border tax laws Global Intangible Low-Taxed Income 26.7 ( 86,241 ) Subpart F Income 0.2 ( 752 ) Tax credits Research and development credit ( 8.6 ) 27,654 Orphan drug credit ( 10.9 ) 35,115 Changes in valuation allowances 2.9 ( 9,373 ) Nontaxable or nondeductible items Stock-based compensation expense ( 28.1 ) 90,695 Nondeductible officers compensation 10.2 ( 32,802 ) Loss related to convertible debt 2.8 ( 8,919 ) Other items 0.7 ( 2,153 ) Changes in unrecognized tax benefits 5.9 ( 18,993 ) Other items ( 1.3 ) 4,114 Effective income tax rate 2.9 % $ ( 9,405 ) (1) State taxes in Kentucky and Massachusetts made up the majority of the tax effect in this category. 128 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS The following table is a reconciliation of our effective income tax rate to the statutory federal income tax rate for the years ended December 31, 2024 and 2023 in accordance with the guidance prior to the adoption of ASU 2023-09: Years Ended December 31, (In thousands) 2024 2023 At U.S. federal statutory rate 21.0 % 21.0 % State taxes, net of federal effect 10.1 8.6 Stock-based compensation expense 9.6 3.9 Tax credits 7.5 6.7 Nondeductible compensation ( 3.8 ) ( 3.0 ) Other permanent items ( 1.8 ) 0.8 Foreign rate differential 2.7 ( 0.7 ) Bermuda tax law enactment — 85.9 Internal reorganization of certain intellectual property rights ( 10.5 ) 12.6 Other ( 1.2 ) 1.7 Uncertain tax position reserve ( 14.3 ) — Revaluation of deferred taxes due to rate change ( 0.6 ) 5.1 Valuation allowance 7.6 ( 144.1 ) Effective income tax rate 26.3 % ( 1.5 ) % The amounts of income tax related taxes paid, net of refunds received were as follows: (In thousands) Year Ended December 31, 2025 State Kentucky $ 7,700 All other 56 Foreign Germany 1,228 Italy 2,847 Brazil 1,210 All other 2,047 Income taxes, net of amounts refunded 15,088 Other taxes 200 Total $ 15,288 129 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Deferred income taxes reflect the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes. We establish a valuation allowance when uncertainty exists as to whether all or a portion of the net deferred tax assets will be realized. Components of the net deferred tax assets were as follows: As of December 31, (In thousands) 2025 2024 Deferred tax assets: Net operating loss carryforwards $ 987,117 $ 882,569 Research and development and other credit carryforwards 452,264 391,642 Liabilities related to the sale of future royalties and development funding 426,826 378,657 Change in fair value of development derivative liability — 107,797 Operating lease liabilities 60,102 60,313 Deferred revenue 1,223 14,515 Deferred compensation 69,981 62,110 Intangible assets 593,725 634,323 Capitalized research and development expenditures 235,622 349,279 Other 90,623 86,425 Total deferred tax assets 2,917,483 2,967,630 Deferred tax liabilities: Property, plant and equipment, net ( 17,367 ) ( 18,596 ) Unrealized gain on marketable securities — ( 2,042 ) Operating lease right-of-use assets ( 41,812 ) ( 41,196 ) Deferred tax asset valuation allowance ( 2,732,329 ) ( 2,788,933 ) Net deferred tax assets $ 125,975 $ 116,863 On July 4, 2025, President Trump signed H.R. 1, the “One Big Beautiful Bill Act,” or the Act, into law. The legislation includes several changes to federal tax law that are designed to allow for more favorable deductibility of certain business expenses and more favorable rules for determining the limitation on business interest expense. The Act includes certain changes to the U.S. taxation of foreign activity, including changes to foreign tax credits, global intangible low-taxed income, foreign-derived intangible income, and base erosion and anti-abuse tax, among other changes. These changes are generally effective for tax years beginning after December 31, 2025, except for changes related to the immediate expensing of research and development expenditures and the reinstatement of 100% bonus depreciation, which were retroactively effective for tax years beginning after December 31, 2024 and for property placed in service after January 19, 2025, respectively. The changes that were retroactively enacted were reflected in the income tax provision for the year ended December 31, 2025 and did not have a material effect on our financial statements. On December 27, 2023, the Government of Bermuda enacted the Corporate Income Tax Act of 2023, or Corporate Income Tax Act, which introduces a corporate income tax regime in Bermuda with a statutory tax rate of 15% effective January 1, 2025. Companies are not subject to income tax in Bermuda prior to this change and with the transition into the Corporate Income Tax Act there is an economic transition adjustment that requires the tax basis of certain Bermudian assets to be established at fair market value. Upon the enactment of the Corporate Income Tax Act, we determined the fair market value of our identifiable intangible assets in Bermuda and recognized a deferred tax asset in our consolidated financial statements for the year ended December 31, 2023. We recorded a full valuation allowance against this deferred tax asset as we had generated historical losses and expected to generate future losses. In the year ended December 31, 2024, we transferred the identifiable intangible assets in Bermuda to Switzerland. We regularly reassess the valuation allowance on our deferred income tax assets. Valuation allowances require an assessment of both positive and negative evidence when determining whether it is more likely than not that we will be able to recover deferred tax assets. Such assessment is required on a jurisdiction-by-jurisdiction basis. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. We assessed the valuation allowance on our Switzerland deferred tax assets and considered positive evidence, including, among other things, income generated in Switzerland in the current year, three-year cumulative Switzerland income, and expected future profitability in Switzerland. After assessing both the positive evidence and negative evidence, we determined it was more likely than not that certain Switzerland deferred tax assets would be realized in the future and released the associated valuation allowance during the year ended December 31, 2024, which resulted in an income tax benefit of $ 108.0 million. 130 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS During the year ended December 31, 2025, we continued to maintain a valuation allowance on certain Switzerland deferred tax assets that may not be realized in future periods. As of December 31, 2025, we maintained a full valuation allowance against our U.S. deferred tax assets. We continue to maintain a valuation allowance on our U.S. deferred tax assets because we have a history of cumulative losses. On a quarterly basis, we reassess the valuation of our U.S. deferred income tax assets weighing positive and negative evidence to assess the recoverability of the deferred tax assets. Based on our recent financial performance and our future projections, we could potentially record a reversal of all or a portion of the U.S. valuation allowance within the foreseeable future. However, any such change is subject to actual performance and other considerations that may present positive or negative evidence at the time of the assessment. The valuation allowance decreased by $ 56.6 million as of December 31, 2025 compared to December 31, 2024, primarily as a result of a change in accounting method that was set up through equity in the amount of $ 71.4 million offset with an increase to the valuation allowance due to additional tax attributes generated of $ 14.8 million. The valuation allowance decreased by $ 28.5 million as of December 31, 2024 compared to December 31, 2023, primarily as a result of the release of the valuation allowance on certain Switzerland deferred tax assets, which primarily consisted of the tax basis in intellectual property transferred from Bermuda and net operating losses, offset by an increase to the valuation allowance due to additional net operating losses in the U.S. The valuation allowance increased by $ 623.0 million as of December 31, 2023 compared to December 31, 2022, primarily due to capitalized research and development costs and internally developed intellectual property. As of December 31, 2025, we had federal and state net operating loss carryforwards, or NOLs, of $ 3.23 billion and $ 3.70 billion, respectively, to reduce future taxable income. Federal NOLs of $ 873.0 million, generated before 2018, will begin expiring in varying amounts through 2037 unless utilized. The remaining federal NOLs of $ 2.36 billion, generated after 2017, will be carried forward indefinitely and could be used to offset up to 80 % of taxable income in all other future tax years. State NOLs will begin expiring in varying amounts through 2045 unless utilized. As of December 31, 2025, we also had foreign NOLs of $ 731.8 million to reduce future taxable income which will begin expiring in varying amounts through 2032. As of December 31, 2025, we had federal research and development, including orphan drug, carryforwards of $ 411.7 million, available to reduce future tax liabilities that expire at various dates through 2045. As of December 31, 2025, we had state research and development and investment tax credit carryforwards of $ 51.4 million, available to reduce future tax liabilities, that expire at various dates through 2040. We have a full valuation allowance against our U.S. federal and state net operating loss and tax credit carryforwards, as well as a valuation allowance against certain foreign net operating loss carryforwards, as we determined it was more likely than not that we would not realize these assets. Ownership changes, as defined in the Internal Revenue Code and similar state provisions, including those resulting from the issuance of common stock in connection with our public offerings, may limit the amount of federal and state net operating loss and tax credit carryforwards that can be utilized to offset future taxable income or tax liability. The amount of the limitation is determined in accordance with Section 382 of the Internal Revenue Code and similar state provisions. We have performed an analysis of ownership changes through December 31, 2025. Based on this analysis, we do not believe that any of our federal and state tax attributes will expire unutilized due to Section 382 limitations. Our reserves related to income taxes are based on a determination of whether, and how much of, a tax benefit taken by us in our tax filings or positions is more likely than not to be realized and ultimately sustained upon challenge by a taxing authority based upon its technical merits and subject to certain recognition and measurement criteria. As of December 31, 2024, we had gross unrecognized tax benefits related to income tax reserves of $ 59.4 million primarily related to federal and state research and orphan drug credit carryforwards. As of December 31, 2025, we had gross unrecognized tax benefits related to income tax reserves primarily related to federal and state research and orphan drug credit carryforwards of $ 78.0 million, of which $ 10.5 million relate to current year positions and $ 9.5 million relate to prior year positions. During the year ended December 31, 2025, the Company settled an Italian audit related to tax years 2020 through 2023 in the amount of $ 1.3 million. We do not have any other material gross unrecognized tax benefits related to income tax reserves. We do not expect any of our unrecognized tax benefits related to income tax reserves, if recognized, to impact our effective tax rate due to full valuation allowance in the U.S. Our policy is to record interest and penalties related to unrecognized tax benefits related to income taxes in our income tax provision. No amounts for interest or penalties related to unrecognized tax benefits have been recognized in our consolidated statements of operations and comprehensive income (loss) for the years ended December 31, 2025, 2024 and 2023. 131 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Years Ended December 31, (In thousands) 2025 2024 Beginning balance $ 59,371 $ — Additions based on tax positions related to current period 10,460 5,080 Additions for tax positions of prior periods 9,467 54,291 Settlements ( 1,329 ) — Ending balance $ 77,969 $ 59,371 We have not recorded a deferred tax liability with respect to excess book over tax outside basis differences, including unremitted earnings and cumulative translation adjustments, in our foreign subsidiary investments, as it is our current intention to permanently reinvest such outside basis differences with certain exceptions. Any permanently reinvested outside basis differences could reverse if we make distributions, sell our foreign subsidiaries or various other events occur, none of which were considered probable as of December 31, 2025. Determination of the amount of deferred tax liabilities described above is not practicable. During the year ended December 31, 2025, we evaluated whether to repatriate cash from certain foreign subsidiaries and determined that any related deferred tax liabilities would not be material to our consolidated financial statements. The tax years 2022 through 2025 remain open to examination by the Internal Revenue Service and certain state tax authorities, although net operating loss and tax credit carryforwards generated prior to 2022 may still be adjusted upon examination by the Internal Revenue Service or state tax authorities if they have or will be used in a future period. 15. EMPLOYEE BENEFITS PLANS We maintain a retirement saving plan under Section 401(k) of the Internal Revenue Code, in which eligible U.S. employees may defer compensation for income tax purposes. Contributions made by employees are limited to the maximum allowable for U.S. federal income tax purposes. The plan allows for a discretionary match in an amount up to 100 % of each participant’s first 4 % of compensation contributed plus 50 % of each participant’s next 2 % of compensation contributed. The expense related to our 401(k) Savings Plan primarily consists of our matching contributions. Furthermore, we maintain defined benefit plans for employees in certain countries outside the U.S., including retirement benefit plans required by applicable local law. The benefit obligation corresponds to the projected benefit obligations of which the discounted net present value is calculated based on years of employment, expected salary increases and pension adjustments. For the years ended December 31, 2025, 2024 and 2023 contributions and net periodic benefit costs to such plans generated a total expense of $ 26.6 million, $ 22.3 million and $ 17.5 million, respectively. 16. SEGMENT INFORMATION We operate in a single segment dedicated to the discovery, development, manufacturing and commercialization of RNAi therapeutics. RNAi therapeutics are comprised of siRNA that function upstream of conventional medicines by potently silencing messenger RNA, or mRNA, that encode for proteins implicated in the cause or pathway of disease, thus preventing them from being made. To date, our efforts have yielded the approval of six first-in-class RNAi-based medicines, which generate the majority of our consolidated total revenues. Consistent with our operational structure, our Chief Executive Officer, or CEO, as the chief operating decision maker, or CODM, manages and allocates resources on a consolidated basis at the global corporate level. Our global research and development and technical operations and quality organizations are responsible for the discovery, development, and supply of products. Commercial efforts that coordinate the marketing, sales and distribution of these products are organized by geographic region and therapeutic area. All of these activities are supported by global corporate staff functions. Managing and allocating resources at the global corporate level enables our CEO to assess the overall level of resources available and how to best deploy these resources in line with our overarching long-term corporate-wide strategic goals. The determination of a single segment is consistent with the consolidated financial information regularly reviewed by the CODM for the purposes of evaluating performance, forecasting future period financial results, allocating resources and setting incentive targets. Consistent with our management reporting, results of our operations are reported on a consolidated basis for purposes of segment reporting. The CEO evaluates performance and decides how to allocate resources based on consolidated net income (loss) that is reported on the consolidated statements of operations and comprehensive income (loss). The measure of segment assets is reported on the consolidated balance sheets as total assets. The CEO uses consolidated net income (loss) to evaluate income generated from the Company’s business activities in deciding how to allocate company resources (such as pursuing clinical development or entering a strategic collaboration), monitoring budget versus actual results, and establishing 132 Table of Contents ALNYLAM PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS management’s compensation. Please refer to the consolidated financial statements for further information related to these measures of segment performance. In addition, research and development and selling, general and administrative expenses are significant segment expenses regularly provided to the CEO with the following categories: Research and Development Years Ended December 31, (In thousands) 2025 2024 2023 Clinical research and outside services $ 640,672 $ 509,129 $ 485,732 Compensation and related 516,208 455,678 357,696 Occupancy and all other costs (1) 162,895 161,425 160,987 Total research and development expense $ 1,319,775 $ 1,126,232 $ 1,004,415 Selling, General and Administrative Years Ended December 31, (In thousands) 2025 2024 2023 Compensation and related $ 668,302 $ 531,078 $ 423,295 Consulting and professional services 348,976 274,539 226,664 Occupancy and all other costs (1) 193,435 169,909 145,687 Total selling, general and administrative expense $ 1,210,713 $ 975,526 $ 795,646 (1) Occupancy and all other costs includes facilities, information technology, depreciation and certain departmental expenses. As of December 31, 2025 and 2024, substantially all of our long-lived assets were from U.S. operations. For the years ended December 31, 2025, 2024 and 2023, net revenues from collaborations were attributed to the U.S. Please refer to Note 3, Net Product Revenues, for information regarding our net product revenues by geography. 133 Table of Contents ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE None. ITEM 9A. CONTROLS AND PROCEDURES Disclosure Controls and Procedures Our management, with the participation of our Chief Executive Officer (principal executive officer) and executive vice president, Chief Financial Officer (principal financial officer), evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2025. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to our management, including its principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of December 31, 2025, our Chief Executive Officer and executive vice president, Chief Financial Officer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level. Management’s Annual Report on Internal Control Over Financial Reporting Our management is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is defined in Rule 13a-15(f) or 15d-15(f) promulgated under the Securities Exchange Act of 1934 as a process designed by, or under the supervision of, our principal executive and principal financial officers and effected by our board of directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that: • Pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of our assets; • Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that our receipts and expenditures are being made only in accordance with authorizations of management and directors; and • Provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of our assets that could have a material effect on the financial statements. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate. Our management assessed the effectiveness of our internal control over financial reporting as of December 31, 2025. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control-Integrated Framework (2013). Based on our assessment, our management concluded that, as of December 31, 2025, our internal control over financial reporting is effective based on those criteria. The effectiveness of our internal control over financial reporting as of December 31, 2025 has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report, which is included herein. Changes in Internal Control There were no changes in our internal control over financial reporting during the quarter ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. ITEM 9B. OTHER INFORMATION Adoption of 10b5-1 Trading Plans by Our Officers and Directors During our fiscal quarter ended December 31, 2025, certain of our officers (as defined in Rule 16a-1(f) under the Exchange Act) and directors entered into written plans for the sale of our securities that are intended to satisfy the conditions specified in 134 Table of Contents Rule 10b5-1(c) under the Exchange Act for an affirmative defense against liability for trading in securities on the basis of material nonpublic information. We refer to these written plans as “Rule 10b5-1 trading plans.” We describe the material terms of the Rule 10b5-1 trading plans below. David E.I. Pyott, Director On November 12, 2025, David E.I. Pyott , a member of our board of directors , entered into a Rule 10b5-1 trading plan that provides that Mr. Pyott, acting through a broker, may sell up to an aggregate of 7,610 shares of our common stock received upon the exercise of options granted to Mr. Pyott as director compensation, subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock. Sales of shares under the plan may only occur if the market price of our common stock is above specified prices from February 11, 2026 to October 14, 2026. The plan is scheduled to terminate on October 14, 2026 , subject to earlier termination upon the sale of all shares subject to the plan, upon termination by Mr. Pyott or the broker, or as otherwise provided in the plan . Pushkal Garg, M.D., Chief Research and Development Officer On November 20, 2025 , Pushkal Garg, M.D . our Chief Research and Development Officer , entered into a Rule 10b5-1 trading plan that provides that Dr. Garg, acting through a broker, may sell up to an aggregate of 25,418 shares of our common stock received upon the settlement of awards granted to Dr. Garg as equity incentive compensation, subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock. Sales of shares under the plan may only occur from February 27, 2026 to November 1, 2026. The plan is scheduled to terminate on November 1, 2026 , subject to earlier termination upon the sale of all shares subject to the plan, upon termination by Dr. Garg or the broker, or as otherwise provided in the plan. Tolga Tanguler, Chief Commercial Officer On November 14, 2025 , Tolga Tanguler , our Chief Commercial Officer , entered into a Rule 10b5-1 trading plan that provides that Mr. Tanguler, acting through a broker, may sell up to an aggregate of 25,782 shares of our common stock received upon the settlement of awards granted to Mr. Tanguler as equity incentive compensation, subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock. Sales of shares under the plan may only occur from February 13, 2026 to November 15, 2026. The plan is scheduled to terminate on November 15, 2026 , subject to earlier termination upon the sale of all shares subject to the plan, upon termination by Mr. Tanguler or the broker, or as otherwise provided in the plan. ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS Not applicable. 135 Table of Contents PART III ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE Incorporated by reference from the information in our Proxy Statement for our 2026 Annual Meeting of Stockholders, or 2026 Proxy Statement, which we will file with the SEC within 120 days of the end of the fiscal year to which this Annual Report on Form 10-K relates. We have an insider trading policy governing the purchase, sale and other dispositions of our securities that applies to all employees, including directors, officers and other covered persons, as well as the Company. We believe that our insider trading policy is reasonably designed to promote compliance with insider trading laws, rules and regulations, as well as applicable listing standards. A copy of our insider trading policy is filed as Exhibit 19.1 to this Annual Report. ITEM 11. EXECUTIVE COMPENSATION The information required under this item is incorporated herein by reference to the information in our 2026 Proxy Statement. ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS The information required under this item is incorporated herein by reference to the information in our 2026 Proxy Statement. Securities Authorized for Issuance Under Equity Compensation Plans We intend to file our 2026 Proxy Statement not later than 120 days after the close of the fiscal year ended December 31, 2025. The information required by this item relating to our equity compensation plans is incorporated herein by reference to the information contained under the section captioned “Supplemental Equity Compensation Plan Information” of the Proxy Statement. ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE The information required under this item is incorporated herein by reference to the information in our 2026 Proxy Statement. ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES The information required under this item is incorporated herein by reference to the information in our 2026 Proxy Statement. 136 Table of Contents PART IV ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES (a) (1) Financial Statements The following consolidated financial statements are filed as part of this report under “Item 8 — Financial Statements and Supplementary Data:” Page Report of Independent Registered Public Accounting Firm (PCAOB ID 238) 91 Consolidated Balance Sheets as of December 31, 2025 and 2024 93 Consolidated Statements of Operations and Comprehensive Income ( Loss ) for the Years Ended December 31, 2025 , 2024 and 2023 94 Consolidated Statements of Stockholders’ Equity (Deficit) for the Years Ended December 31, 2025 , 2024 and 2023 95 Consolidated Statements of Cash Flows for the Years Ended December 31, 2025 , 2024 and 2023 96 Notes to Consolidated Financial Statements 97 (a) (2) List of Schedules All schedules to the consolidated financial statements are omitted as the required information is either inapplicable or presented in the consolidated financial statements. (a) (3) List of Exhibits Exhibit No. Exhibit 3.1 Restated Certificate of Incorporation of the Registrant (filed as Exhibit 3.1C to the Registrant’s Current Report on Form 8-K filed on April 26, 2019 (File No. 001-36407) and incorporated herein by reference) 3.2 Certificate of Amendment to Restated Certificate of Incorporation of Alnylam Pharmaceuticals, Inc. (filed as Exhibit 3.1 to the Registrant’s Current Report on Form 8-K filed on May 13, 2025 (File No. 001-36407) and incorporated herein by reference) 3.3 Second Amended and Restated Bylaws of the Registrant, as amended (filed as Exhibit 3.1 to the Registrant’s Quarterly Report on Form 10-Q filed on November 5, 2020 (File No. 001-36407) for the quarterly period ended September 30, 2020 and incorporated herein by reference) 4.1 Specimen certificate evidencing shares of common stock (filed as Exhibit 4.1 to the Registrant’s Registration Statement on Form S-1 (File No. 333-113162) and incorporated herein by reference) 4.2 Description of Capital Stock (filed as Exhibit 4.2 to the Registrant’s Annual Report on Form 10-K filed on February 13, 2020 (File No. 001-36407) for the year ended December 31, 2019 and incorporated herein by reference)