Item 7. Management's Discussion and Analysis of Financial Condition and Results and Results of Operations

The following discussion should be read in conjunction with the consolidated financial statements and related notes included elsewhere in this report. Refer to Part II, Item 7 in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 (filed with the SEC on February 6, 2023) for additional discussion of our financial condition and results of operations for the year ended December 31, 2021, as well as our financial condition and results of operations for the year ended December 31, 2022 compared to the year ended December 31, 2021.

Overview

Regeneron Pharmaceuticals, Inc. is a fully integrated biotechnology company that invents, develops, manufactures, and commercializes medicines for people with serious diseases. Our research and development efforts have led to eleven FDA-approved products that have received marketing approval and approximately 35 product candidates in clinical development, almost all of which were homegrown in our laboratories.

Our ability to generate profits and to generate positive cash flow from operations over the next several years depends significantly on the continued success in commercializing EYLEA and Dupixent, as well as whether we are successful in commercializing EYLEA HD. We expect to continue to incur substantial expenses related to our research and development activities, a portion of which we expect to be reimbursed by our collaborators. In addition, our research and development activities and related costs which are not reimbursed are expected to expand and require additional resources. We also expect to incur substantial costs related to the commercialization of our marketed products. Our financial results may fluctuate from quarter to quarter and will depend on, among other factors, the net sales of our products; the scope and progress of our research and development efforts; the timing of certain expenses; the continuation of our collaborations, in particular with Sanofi and Bayer, including our share of collaboration profits from sales of commercialized products and the amount of reimbursement of our research and development expenses that we receive from collaborators; and the amount of income tax expense we incur, which is partly dependent on the profits or losses we earn in each of the countries in which we operate. We cannot predict whether or when new products or new indications for marketed products will receive regulatory approval or, if any such approval is received, whether we will be able to successfully commercialize such product(s) and whether or when they may become profitable.

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Critical Accounting Estimates

The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect reported amounts and related disclosures in the financial statements. Critical accounting estimates are those estimates made in accordance with GAAP that involve a significant level of estimation uncertainty and have had or are reasonably likely to have a material impact on our results of operations or financial condition.

Management believes the current assumptions used to estimate amounts reflected in our Consolidated Financial Statements are appropriate. However, if actual experience differs from the assumptions used in estimating amounts reflected in our Consolidated Financial Statements, the resulting changes could have a material adverse effect on our results of operations, and, in certain situations, could have a material adverse effect on our liquidity and financial condition. The critical accounting estimates that impact our Consolidated Financial Statements are described below.

Product Revenue

We recognize revenue from product sales at a point in time when our customer is deemed to have obtained control of the product, which generally occurs upon receipt or acceptance by our customer. The amount of revenue we recognize from product sales may vary due to rebates, chargebacks, and discounts provided under governmental and other programs, distribution-related fees, and other sales-related deductions. In order to determine the transaction price, we estimate, utilizing the expected value method, the amount of variable consideration to which we will be entitled. This estimate is based upon contracts with customers, healthcare providers, payors and government agencies, statutorily-defined discounts applicable to government-funded programs, historical experience, estimated payor mix, and other relevant factors. Calculating these provisions involves estimates and judgments. We review our estimates of rebates, chargebacks, and other applicable provisions each period and record any necessary adjustments in the current period's net product sales. Refer to the "Results of Operations - Revenues - Net Product Sales" section below for further details regarding our provisions, and credits/payments, for sales-related deductions.

Collaborative Arrangements

We have entered into various collaborative arrangements to research, develop, manufacture, and commercialize products and/or product candidates. Our collaboration agreements may require us to deliver various rights, services, and/or goods across the entire life cycle of a product or product candidate. In agreements involving multiple goods or services promised to be transferred to our collaborator, we assess, at the inception of the contract, whether each promise represents a separate obligation (i.e., is "distinct"), or whether such promises should be combined as a single unit of account. When we have a combined unit of account which includes a license and providing research and development services to our collaborator, recognition of up-front payments and development milestones earned from our collaborator is deferred (as a liability) and recognized over the development period (i.e., over time) typically using an input method on the basis of our research and development costs incurred relative to the total expected cost which determines the extent of our progress toward completion. We review our estimates each period and make revisions to such estimates as necessary. Due to the variability in the scope of activities and length of time necessary to develop a drug product, potential delays in development programs, changes to development plans and budgets as programs progress, including if we and our collaborators decide to expand or contract our clinical plans for a drug candidate in various disease indications, and uncertainty in the ultimate requirements to obtain governmental approval for commercialization, revisions to our estimates are likely to occur periodically, potentially resulting in material changes to amounts recognized.

If our collaborator performs research and development work or commercialization-related activities and the parties share the related costs, we also recognize, as expense (e.g., research and development expense or selling, general and administrative expense, as applicable) in the period when our collaborator incurs such expenses, the portion of the collaborator's expenses that we are obligated to reimburse. Our collaborators provide us with estimated expenses for the most recent fiscal quarter. The estimates are revised, if necessary, in subsequent periods if actual expenses differ from those estimates.

Under certain of the Company's collaboration agreements, product sales and cost of sales may be recorded by the Company's collaborators as they are deemed to be the principal in the transaction. In arrangements where we:

•supply commercial product to our collaborator, we may be reimbursed for our manufacturing costs as commercial product is shipped to the collaborator (however, recognition of such cost reimbursements may be deferred until the product is sold by our collaborator to third-party customers);

•share in any profits or losses arising from the commercialization of such products, we record our share of the variable consideration, representing net product sales less cost of goods sold and shared commercialization and other expenses, in the period in which such underlying sales occur and costs are incurred by the collaborator;

•receive royalties and/or sales-based milestone payments from our collaborator, we recognize such amounts in the period earned.

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Our collaborators provide us with estimates of product sales and our share of profits or losses, as applicable, for each quarter. The estimates are revised, if necessary, in subsequent periods if our actual share of profits or losses differ from those estimates.

Stock-based Compensation

We recognize stock-based compensation expense for equity grants under our long-term incentive plans to employees and non-employee members of our board of directors (as applicable) based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Stock-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. This estimate is revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. In addition, we reassess our forfeiture rate assumptions at least annually, considering both historical forfeiture experience and an estimate of future forfeitures for currently outstanding unvested awards. The assumptions used in computing the fair value of equity awards reflect our best estimates but involve uncertainties related to market and other conditions, many of which are outside our control. Changes in any of these assumptions may materially affect the fair value of awards granted and the amount of stock-based compensation recognized in future periods.

We use the Black-Scholes model to compute the estimated fair value of stock option awards. Using this model, fair value is calculated based on assumptions with respect to (i) expected volatility of our Common Stock price, (ii) the periods of time over which employees and members of our board of directors are expected to hold their options prior to exercise (expected lives), (iii) expected dividend yield on our Common Stock, and (iv) risk-free interest rates, which are based on quoted U.S. Treasury rates for securities with maturities approximating the options' expected lives. Expected volatility is estimated based on actual movements in our stock price over the most recent historical periods equivalent to the options' expected lives. Expected lives are principally based on our historical exercise experience with previously issued employee and board of director option grants. The expected dividend yield is zero as we have never paid dividends and do not currently have plans to do so.

We use a Monte Carlo simulation to compute the estimated fair value of performance-based restricted stock units that are subject to vesting based on the Company's attainment of pre-established criteria that include a market condition.

For performance-based restricted stock units that contain a performance condition, we recognize stock-based compensation expense if and when we determine that it is probable the performance condition will be achieved (based on the number of shares expected to be vested and issued). We reassess the probability of achievement at each reporting period and adjust compensation cost, as necessary. If there are any changes in our probability assessment, we recognize a cumulative catch-up adjustment in the period of the change in estimate, with the remaining unrecognized expense recognized prospectively over the remaining requisite service period. If we subsequently determine that the performance criteria are not met or are not expected to be met, any amounts previously recognized as compensation expense are reversed in the period when such determination is made.

See Note 13 to our Consolidated Financial Statements for stock-based compensation expense and related assumptions used in determining the fair value of our awards.

Income Taxes

We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns, including deferred tax assets and liabilities for expected amounts of global intangible low-taxed income ("GILTI") inclusions. Deferred tax assets and liabilities are determined as the difference between the tax basis of assets and liabilities and their respective financial reporting amounts ("temporary differences") at enacted tax rates in effect for the years in which the differences are expected to reverse. A valuation allowance is established for deferred tax assets for which it is more likely than not that some portion or all of the deferred tax assets will not be realized. We periodically re-assess the need for a valuation allowance against our deferred tax assets based on all available evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies, results of recent operations, and our historical earnings experience by taxing jurisdiction. Significant judgment is required in making this assessment.

We recognize the financial statement effects of a tax position when our assessment is that there is more than a 50% probability that the position will be sustained upon examination by a taxing authority based upon its technical merits. Uncertain tax positions are recorded based upon certain recognition and measurement criteria. Significant judgment is required in making this assessment, and, therefore, we re-evaluate uncertain tax positions and consider various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, information obtained during in-process audit activities, and changes in facts or circumstances related to a tax position. We adjust the amount of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain tax positions.

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Inventories

We capitalize inventory costs associated with our products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval.

We periodically analyze our inventory levels to identify inventory that 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. In addition, our products are subject to strict quality control and monitoring which we perform throughout the manufacturing process. If certain batches or units of product no longer meet quality specifications or become obsolete due to expiration, we record a charge to write down such inventory to its estimated realizable value.

See "Results of Operations - Expenses - Cost of Goods Sold" below for further information related to our inventory write-offs and reserves.

Acquisitions

We make certain judgments to determine whether a transaction should be accounted for as a business combination or as an asset acquisition. In a business combination, the acquisition method of accounting generally requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values. There can be significant judgment involved in determining the estimated fair values of such assets and liabilities. Amounts allocated to acquired in-process research and development are capitalized as indefinite-lived intangible assets. Any excess of the purchase price (consideration transferred) over the fair values of net assets acquired is recorded as goodwill. In a business combination, contingent consideration obligations are recorded at fair value as of the acquisition date and remeasured each subsequent reporting period until the contingencies have been resolved. The fair value of contingent consideration liabilities is determined using inputs that may include the probability of achieving certain milestones and estimated discount rates.

If it is determined that the assets acquired do not meet the definition of a business, or if substantially all of the fair value of the assets acquired are concentrated in a single identifiable asset, then the transaction is accounted for as an asset acquisition rather than a business combination. In an asset acquisition, assets acquired are recorded at cost, goodwill is not recorded, and acquired in-process research and development with no alternative future use is charged to expense.

Intangible Assets

Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in connection with an asset acquisition are recorded at cost.

Payments to acquire intangible assets in an asset acquisition may include up-front payments and contingent consideration. With regard to contingent consideration in an asset acquisition, the Company recognizes regulatory milestones upon achievement, royalties in the period in which the underlying sales occur, and sales-based milestones when the milestone is deemed probable by the Company of being achieved. If contingent consideration is recognized subsequent to the acquisition date in an asset acquisition, the amount of such consideration is recorded as an addition to the cost basis of the intangible asset with a cumulative catch-up adjustment for amortization expense as if the additional amount of consideration had been accrued from the outset of the acquisition.

Indefinite-lived intangible assets are subject to impairment testing until completion or abandonment of the associated research and development efforts. Definite-lived intangible assets are amortized over the estimated useful lives of the assets based on the pattern in which the economic benefits of the intangible assets are consumed; if that pattern cannot be reliably determined, a straight-line basis is used.

Intangible assets are reviewed for recoverability whenever events or changes in circumstances (e.g., changes in economic, regulatory, or legal conditions) indicate that the carrying amount of the asset may not be recoverable. If an indicator of impairment exists, we compare the projected undiscounted cash flows to be generated by the asset to the intangible asset's carrying amount. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, the intangible asset is written down to its fair value in the period in which the impairment occurs.

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Contingencies

We accrue, based on management's judgment, for an estimated loss when the potential loss from claims or legal proceedings is considered probable and the amount can be reasonably estimated. As additional information becomes available, or, based on specific events such as the outcome of litigation or settlement of claims, we reassess the potential liability related to pending claims and litigation, and may change our estimates.

Results of Operations

Net Income

Year Ended December 31,

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Revenues

Year Ended December 31, $ Change

Net product sales:

EYLEA HD - U.S. $ 165.8 $ — $ — $ 165.8 $ —

ARCALYST - U.S.** — — 2.2 — (2.2)

Collaboration revenue:

Net Product Sales

Net product sales of EYLEA in the United States decreased in 2023, compared to 2022, primarily due to changing market dynamics, resulting in a lower net selling price and lower volumes. EYLEA volumes in 2023 were impacted by the August 2023 launch of EYLEA HD and subsequent transition of EYLEA patients to EYLEA HD.

During the year ended December 31, 2021, we recorded net product sales of REGEN-COV in connection with our agreements with the U.S. government. As of December 31, 2021, the Company had completed its final deliveries of drug product under its agreements with the U.S. government; as a result, there were no net product sales of REGEN-COV in the United States recorded during the years ended December 31, 2023 and 2022.

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Revenue from product sales is recorded net of applicable provisions for rebates, chargebacks, and discounts; distribution-related fees; and other sales-related deductions. The following table summarizes the provisions, and credits/payments, for sales-related deductions.

Sanofi Collaboration Revenue

Year Ended December 31,

Antibody:

Reimbursement for manufacturing of commercial supplies(a) 613.0 633.7 488.8

Total Immuno-oncology(b) — 11.3 0.4

Antibody

Global net product sales of Dupixent and Kevzara are recorded by Sanofi in connection with the Antibody Collaboration, and we and Sanofi share profits on such sales. As described in Part I, Item 1. "Business - Collaboration, License, and Other Agreements - Sanofi - Antibody", on July 1, 2022, an amendment to the LCA became effective, pursuant to which the percentage of Regeneron's share of profits in any calendar quarter used to reimburse Sanofi for development costs which were funded by Sanofi increased from 10% to 20%.

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Regeneron's share of profits in connection with the commercialization of Dupixent and Kevzara is summarized below:

Year Ended December 31,

The increase in our share of profits in connection with commercialization of antibodies during the year ended December 31, 2023, compared to 2022, was driven by higher profits associated with Dupixent sales, partly offset by the impact of the amendment to the LCA.

During the year ended December 31, 2023, the Company earned the final $50.0 million sales-based milestone from Sanofi, upon aggregate annual sales of antibodies outside the United States (including Praluent) exceeding $3.0 billion on a rolling twelve-month basis. During the year ended December 31, 2022, the Company earned two $50.0 million sales-based milestones from Sanofi, upon aggregate annual sales of antibodies outside the United States (including Praluent) exceeding $2.0 billion and $2.5 billion, respectively, on a rolling twelve-month basis.

Reimbursements for manufacturing of commercial supplies primarily relate to Dupixent and are recognized when the product is sold by Sanofi to third-party customers; such reimbursements decreased during the year ended December 31, 2023, compared to 2022, primarily due to lower manufacturing costs resulting from the transition to a higher-yielding manufacturing process.

Bayer Collaboration Revenue

Year Ended December 31,

One-time payment in connection with change in Japan arrangement(b) — 21.9 —

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Bayer records net product sales of EYLEA outside the United States. Regeneron's share of profits in connection with commercialization of EYLEA outside the United States is summarized below:

Year Ended December 31,

EYLEA net product sales outside the United States $ 3,495.2 $ 3,382.8 $ 3,450.9

Roche Collaboration Revenue

Year Ended December 31,

Other (13.3) — —

Roche distributes and records net product sales of Ronapreve outside the United States, and the parties share gross profits from worldwide sales.

Other Revenue

Other revenue in 2023 included the recognition of $50.4 million of revenue in connection with our August 2023 agreement with BARDA to fund certain costs for a next-generation COVID-19 monoclonal antibody therapy for the prevention of SARS-CoV-2 infection. In addition, Other revenue increased in 2023, compared to 2022, primarily due to the following:

•higher reimbursements for the manufacture of commercial supplies for Sanofi related to Praluent outside the United States;

•higher share of profits earned in connection with sales of ARCALYST pursuant to our license agreement with Kiniksa Pharmaceuticals, Ltd.; and

•royalties earned in connection with our license agreement with Novartis, under which we receive royalties on worldwide sales of Novartis' Ilaris® (canakinumab).

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Expenses

Year Ended December 31, Change

Operating expenses in 2023 and 2022 included a total of $885.0 million and $725.0 million, respectively, of stock-based compensation expense related to equity awards granted under our long-term incentive plans. As of December 31, 2023, unrecognized stock-based compensation expense related to unvested stock options and unvested restricted stock (including performance-based restricted stock units) was $589.6 million and $1.127 billion, respectively. We expect to recognize this stock-based compensation expense related to stock options and restricted stock over weighted-average periods of 1.8 years and 2.3 years, respectively.

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Research and Development Expenses

The following table summarizes our direct research and development expenses by clinical development program and other significant categories of research and development expenses. Direct research and development expenses are comprised primarily of costs paid to third parties for clinical and product development activities, including costs related to preclinical research activities, clinical trials, and the portion of research and development expenses incurred by our collaborators that we are obligated to reimburse. Indirect research and development expenses have not been allocated directly to each program, and primarily consist of costs to compensate personnel, overhead and infrastructure costs to maintain our facilities, and other costs related to activities that benefit multiple projects. Clinical manufacturing costs primarily consist of costs to manufacture bulk drug product for clinical development purposes as well as related drug filling, packaging, and labeling costs. Clinical manufacturing costs also includes pre-launch commercial supplies which did not meet the criteria to be capitalized as inventory (see "Critical Accounting Policies and Use of Estimates - Inventories" above). The table below also includes reimbursements of research and development expenses by collaborators, as when we are entitled to reimbursement of all or a portion of such expenses that we incur under a collaboration, we record those reimbursable amounts in the period in which such costs are incurred.

Year Ended December 31, $ Change

Direct research and development expenses:

Indirect research and development expenses:

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Total research and development expenses increased in 2023, compared to 2022, partially due to the impact of the amendments to the Sanofi collaboration agreements (which were effective July 1, 2022) described above in Part I, Item 1. "Business - "Collaboration, License, and Other Agreements - Sanofi", as (i) Sanofi is no longer reimbursing us for 50% of Libtayo development costs (such reimbursements were previously included in Reimbursement of research and development expenses by collaborators in the table above) and (ii) we recognize our 50% share of research and development expenses in connection with the Sanofi Antibody Collaboration.

Research and development expenses included stock-based compensation expense of $488.7 million and $406.8 million in 2023 and 2022, respectively.

There are numerous uncertainties associated with drug development, including uncertainties related to safety and efficacy data from each phase of drug development, uncertainties related to the enrollment and performance of clinical trials, changes in regulatory requirements, changes in the competitive landscape affecting a product candidate, and other risks and uncertainties described in Part I, Item 1A. "Risk Factors." There is also variability in the duration and costs necessary to develop a pharmaceutical product, potential opportunities and/or uncertainties related to future indications to be studied, and the estimated cost and scope of the projects. The lengthy process of seeking FDA and other applicable approvals, and subsequent compliance with applicable statutes and regulations, require the expenditure of substantial resources. Any failure by us to obtain, or delay in obtaining, regulatory approvals could materially adversely affect our business. We are unable to reasonably estimate if our product candidates in clinical development will generate material product revenues and net cash inflows.

Acquired In-process Research and Development ("IPR&D")

Acquired IPR&D in 2023 included:

•$100.0 million charge in connection with a development milestone for the Phase 1 ALN-APP program, which is in collaboration with Alnylam;

•$45.0 million up-front payment in connection with our collaboration agreement with Sonoma Biotherapeutics, Inc.; and

•$30.0 million charge to extend the period for selecting targets under our collaboration agreement with Intellia.

Acquired IPR&D in 2022 included:

•$195.0 million charge related to our acquisition of Checkmate Pharmaceuticals, Inc.;

•$30.0 million up-front payment in connection with our collaboration agreement with CytomX Therapeutics, Inc.; and

•$20.0 million opt-in payment in connection with a product candidate under our collaboration agreement with Adicet Bio, Inc.

Selling, General, and Administrative Expenses

Selling, general, and administrative expenses increased in 2023, compared to 2022, primarily due to higher headcount and headcount-related costs, an increase in commercialization-related expenses for Libtayo (including acquisition and integration-related costs for Libtayo outside the United States as effective July 1, 2022, the Company became solely responsible for the commercialization of Libtayo worldwide), and, to a lesser extent, commercialization-related expenses for various other products, and higher contributions to an independent not-for-profit patient assistance organization. Selling, general, and administrative expenses also included $307.1 million and $256.4 million of stock-based compensation expense in 2023 and 2022, respectively.

Cost of Goods Sold

Cost of goods sold increased in 2023, compared to 2022, primarily due to higher start-up costs for our Rensselaer, New York fill/finish facility and an increase in period costs at our manufacturing facilities resulting from lower production volumes, partly offset by lower inventory write-offs and reserves. Inventory write-offs and reserves were $102.3 million in 2023 compared to $258.7 million in 2022. The inventory write-offs and reserves in 2022 were primarily related to REGEN-COV.

Cost of Collaboration and Contract Manufacturing

Cost of collaboration and contract manufacturing increased in 2023, compared to 2022, primarily due to the recognition of costs in connection with manufacturing commercial supplies for Sanofi related to Praluent outside the United States and for Bayer related to EYLEA outside the United States. This increase was partly offset by lower Dupixent manufacturing costs as a result of the transition to a higher-yielding manufacturing process.

Other Operating (Income) Expense

Other operating (income) expense, net, in 2022 included the recognition of amounts previously deferred in connection with up-front and development milestone payments, as applicable, received in connection with our Sanofi IO, Teva, and Mitsubishi

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Tanabe Pharma Corporation ("MTPC") collaborative arrangements. As we discontinued further clinical development of fasinumab (for which we had collaborative arrangements with Teva and MTPC) during 2022, and the A&R IO LCA with Sanofi became effective July 1, 2022, no such amounts were recognized in connection with these collaborative arrangements during 2023.

Other Income (Expense)

Other income (expense) consists of the following:

Year Ended December 31,

Unrealized (losses) gains on equity securities, net $ (237.8) $ (39.8) $ 386.1

Foreign currency (losses) gains (12.9) 50.2 0.4

The increase in interest income in 2023, compared to 2022, was primarily driven by higher interest rates.

Income Taxes

Year Ended December 31,

The Company's effective tax rate for 2023, compared to 2022, included a higher benefit from stock-based compensation, federal tax credits for research activities, and the proportion of income earned in foreign jurisdictions with tax rates lower than the U.S. federal statutory rate.

Certain countries in which we have operations, including Ireland, have adopted legislation influenced by the OECD Pillar Two rules, including a minimum tax rate of 15%. It is uncertain whether the United States will enact legislation to adopt the Pillar Two framework. While we do not expect the adoption of the Pillar Two framework to have a material impact on our effective tax rate, we are continuing to evaluate additional guidance released by the OECD, along with the pending legislative adoption by additional individual countries.

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Liquidity and Capital Resources

Our financial condition is summarized as follows:

As of December 31,

Financial assets:

Working capital:

Borrowings and finance lease liabilities:

Finance lease liabilities $ 720.0 $ 720.0 $ —

As of December 31, 2023, we also had borrowing availability of $750.0 million under a revolving credit facility (see further description under "Credit Facility" below).

Sources and Uses of Cash for the Years Ended December 31, 2023, 2022, and 2021

Year Ended December 31, $ Change

Cash Flows from Operating Activities

As of December 31, 2023 and 2022, deferred tax assets increased by $837.8 million and $746.4 million, respectively, primarily related to the impact of the Tax Cuts and Jobs Act of 2017, which requires, for tax purposes, the capitalization and amortization of research and development expenses effective for years beginning after December 31, 2021.

As of December 31, 2021, Accounts receivable increased by $1.927 billion, compared to December 31, 2020, primarily due to REGEN-COV sales in connection with our September 2021 agreement to supply drug product to the U.S. government. As of December 31, 2022, Accounts receivable had decreased by $707.8 million, compared to December 31, 2021, driven by the Company's collection of amounts due from the U.S. government in connection with such sales in the fourth quarter of 2021.

Other non-cash items, net, in 2022 and 2021 included inventory write-offs and reserves primarily related to REGEN-COV.

Cash Flows from Investing Activities

Capital expenditures in 2023 included costs incurred in connection with the expansion of our Tarrytown, New York location, as well as costs associated with the expansion of our manufacturing facilities in Rensselaer, New York (including the ongoing construction of a fill/finish facility and related equipment). Additionally, capital expenditures in 2023 is net of grant proceeds of $60.0 million primarily related to the expansion of our facilities in New York. We expect to incur capital expenditures of $825 million to $950 million in 2024 primarily in connection with the continued expansion of our research, preclinical manufacturing, and support facilities at our Tarrytown, New York campus and our manufacturing facilities. We expect continued significant capital expenditures over the next several years in connection with the planned expansion of our Tarrytown, New York campus.

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Payments for the Libtayo intangible asset of $207.8 million and $1.027 billion in 2023 and 2022, respectively, were related to our acquisition (including contingent consideration paid) of the exclusive right to develop, commercialize, and manufacture Libtayo worldwide (as described in Part I, Item 1. "Collaboration, License, and Other Agreements - Sanofi - Immuno-Oncology" above).

Acquisitions, net of cash acquired, of $54.9 million and $230.3 million in 2023 and 2022 was related to our acquisitions of Decibel Therapeutics, Inc. and Checkmate Pharmaceuticals, Inc., respectively.

Cash Flows from Financing Activities

Proceeds from issuances of Common Stock, in connection with exercises of employee stock options, were $1.146 billion during 2023, compared to $1.520 billion during 2022 and $1.672 billion during 2021. For information related to repurchases of Common Stock, see "Share Repurchase Programs" section below.

Credit Facility

In December 2022, we entered into an agreement with a syndicate of lenders (the "2022 Credit Agreement") which provides for a $750.0 million senior unsecured five-year revolving credit facility (the "2022 Credit Facility") and replaced the then-existing credit agreement, which was contemporaneously terminated. The 2022 Credit Agreement includes an option for the Company to elect to increase the commitments under the 2022 Credit Facility and/or to enter into one or more tranches of term loans in the aggregate principal amount of up to $500.0 million, subject to the consent of the lenders providing the additional commitments or term loans, as applicable, and certain other conditions. The 2022 Credit Agreement also provides a $50.0 million sublimit for letters of credit.

As set forth in the 2022 Credit Agreement, we have the option to amend the 2022 Credit Agreement to establish environmental, social, and governance targets which will be used to adjust pricing under the 2022 Credit Facility, subject to parameters to be provided in the 2022 Credit Agreement.

Proceeds of the loans under the 2022 Credit Facility may be used to finance working capital needs, and for general corporate or other lawful purposes, of Regeneron and its subsidiaries. Regeneron Pharmaceuticals, Inc. has guaranteed all obligations under the 2022 Credit Facility. The 2022 Credit Agreement includes an option for us to elect to extend the maturity date of the 2022 Credit Facility beyond December 2027, subject to the consent of the extending lenders and certain other conditions. Amounts borrowed under the 2022 Credit Facility may be prepaid, and the commitments under the 2022 Credit Facility may be terminated, at any time without premium or penalty.

We had no borrowings outstanding under the 2022 Credit Facility as of December 31, 2023.

The 2022 Credit Agreement contains operating covenants and a maximum total leverage ratio financial covenant. We were in compliance with all covenants of the 2022 Credit Agreement as of December 31, 2023.

Share Repurchase Programs

In January 2021, our board of directors authorized a share repurchase program to repurchase up to $1.5 billion of our Common Stock. As of December 31, 2021, the Company had repurchased the entire $1.5 billion of its Common Stock that it was authorized to repurchase under the program.

In November 2021, our board of directors authorized a share repurchase program to repurchase up to $3.0 billion of our Common Stock. As of June 30, 2023, the Company had repurchased the entire $3.0 billion of its Common Stock that it was authorized to repurchase under the program.

In January 2023, our board of directors authorized an additional share repurchase program to repurchase up to $3.0 billion of our Common Stock. The share repurchase program permits the Company to make repurchases through a variety of methods, including open-market transactions (including pursuant to a trading plan adopted in accordance with Rule 10b5-1 of the Exchange Act), privately negotiated transactions, accelerated share repurchases, block trades, and other transactions in compliance with Rule 10b-18 of the Exchange Act. Repurchases may be made from time to time at management's discretion, and the timing and amount of any such repurchases will be determined based on share price, market conditions, legal requirements, and other relevant factors. The program has no time limit and can be discontinued at any time. There can be no assurance as to the timing or number of shares of any repurchases in the future. As of December 31, 2023, $1.531 billion remained available for share repurchases under the program.

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The table below summarizes the shares of our Common Stock we repurchased and the cost of the shares, which were recorded as Treasury Stock.

Year Ended December 31,

Tarrytown, New York Lease

We are party to a Third Amended and Restated Lease and Remedies Agreement, dated March 27, 2023 (the "Third Amended and Restated Lease") with BA Leasing BSC, LLC, an affiliate of Banc of America Leasing & Capital, LLC ("BAL"), as lessor, which relates to our lease of laboratory and office facilities in Tarrytown, New York (the "Facility"); and a Third Amended and Restated Participation Agreement, dated March 27, 2023 (the "Third Amended and Restated Participation Agreement") with Bank of America, N.A., as administrative agent (the "Administrative Agent"), and a syndicate of lenders (collectively with BAL, the "Participants"), as rent assignees. The Third Amended and Restated Lease and Third Amended and Restated Participation Agreement provide for a March 2027 maturity date of the $720.0 million lease financing (previously advanced by the Participants in March 2017 in connection with the acquisition by BAL of the Facility and our lease of the Facility from BAL) and the end of the term of our lease of the Facility from BAL, at which time all amounts outstanding thereunder will become due and payable in full.

In accordance with the terms of the Third Amended and Restated Lease, we pay all maintenance, insurance, taxes, and other costs arising out of the use of the Facility. We are also required to make monthly payments of basic rent during the remaining term of the Third Amended and Restated Lease to satisfy the yield payable to the Participants on their outstanding advances under the Third Amended and Restated Participation Agreement. Such advances accrue yield at a variable rate per annum based on the one-month forward-looking Secured Overnight Financing Rate ("SOFR") term rate, plus a spread adjustment, plus an applicable margin that varies with our debt rating and total leverage ratio.

The Third Amended and Restated Participation Agreement and Third Amended and Restated Lease include an option for us to elect to further extend the maturity date of the Third Amended and Restated Participation Agreement and the term of the Third Amended and Restated Lease for an additional five-year period, subject to the consent of all the Participants and certain other conditions. We also have the option prior to the end of the term of the Third Amended and Restated Lease to (a) purchase the Facility by paying an amount equal to the outstanding principal amount of the Participants' advances under the Third Amended and Restated Participation Agreement, all accrued and unpaid yield thereon, and all other outstanding amounts under the Third Amended and Restated Participation Agreement, Third Amended and Restated Lease, and certain related documents or (b) sell the Facility to a third party on behalf of BAL.

The Third Amended and Restated Lease is classified as a finance lease as we have the option to purchase the Facility under terms that make it reasonably certain to be exercised. The agreements governing the Third Amended and Restated Lease financing contain financial and operating covenants. Such financial covenants and certain of the operating covenants are substantially similar to the covenants set forth in our 2022 Credit Agreement. The Company was in compliance with all such covenants as of December 31, 2023.

Additional Funding Requirements

The amount required to fund operations will depend on various factors, including the potential regulatory approval and commercialization of our product candidates and the timing thereof and the extent and cost of our research and development programs. We believe that our existing capital resources, borrowing availability under the 2022 Credit Facility, funds generated by anticipated product sales, and funding for reimbursement of research and development costs that we are entitled to receive under our collaboration agreements, will enable us to meet our anticipated operating needs for the foreseeable future.

We expect to continue to incur significant costs in connection with our research and development activities (including preclinical and clinical programs). The amount of funding that will be required for our clinical programs depends upon the results of our research and preclinical programs and early-stage clinical trials, regulatory requirements, the duration and results of clinical trials underway and of additional clinical trials that we decide to initiate, and the various factors that affect the cost of each trial, including the size of trials, fees charged for services provided by clinical trial investigators and other third parties, the costs for manufacturing the product candidate for use in the trials, and other expenses.

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We also anticipate continuing to incur substantial commercialization costs for our marketed products. Commercialization costs over the next few years will depend on, among other things, the market potential for product candidates, whether commercialization costs are shared with a collaborator, and regulatory approval of additional product candidates.

We expect that expenses related to the filing, prosecution, defense, and enforcement of patents and other intellectual property will be substantial.

Liabilities for unrecognized tax benefits totaled $696.4 million as of December 31, 2023. Due to their nature, there is a high degree of uncertainty regarding the period and amounts of potential future cash settlement with tax authorities. See Note 15 to our Consolidated Financial Statements.

We enter into collaboration and licensing agreements that may require us to pay (i) 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, and/or (ii) royalties calculated based on a percentage of net product sales. The payment of these amounts, however, is contingent upon the occurrence of various future events, which have a high degree of uncertainty of occurring and for which the specific timing cannot be predicted. See Note 3 to our Consolidated Financial Statements.

As described in Part I, Item 1. "Collaboration, License, and Other Agreements," under our collaborations with Bayer and Sanofi, we and our collaborator share profits in connection with commercialization of drug products. If the applicable collaboration is profitable, we have contingent contractual obligations to reimburse Bayer and Sanofi for a defined percentage (generally 50%) of agreed-upon development expenses funded by Bayer and Sanofi (i.e., "development balance"). These reimbursements are deducted each quarter, in accordance with a formula, from our share of the collaboration profits otherwise payable to us, unless, in the case of Bayer, we elect to reimburse these expenses at a faster rate. As of December 31, 2023, our contingent reimbursement obligation to Bayer was approximately $293 million and our contingent reimbursement obligation to Sanofi in connection with the companies' Antibody Collaboration was approximately $2.330 billion. Therefore, we continue to expect that a portion of our share of profits from sales under our collaborations with Bayer and Sanofi will be used to reimburse our collaborators for these obligations.

Future Impact of Recently Issued Accounting Standards

See Note 1 to our Consolidated Financial Statements for a description of recently issued accounting standards.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

Interest Rate Risk

Our earnings and cash flows are subject to fluctuations due to changes in interest rates, principally in connection with our investments in marketable securities, which consist primarily of corporate bonds and U.S. treasury securities. We do not believe we are materially exposed to changes in interest rates related to our investments, and we do not currently use interest rate derivative instruments to manage exposure to interest rate changes of our investments. We estimate that a 100 basis point, or 1%, unfavorable change in interest rates would have resulted in approximately a $98.7 million and $102.7 million decrease in the fair value of our investment portfolio as of December 31, 2023 and 2022, respectively.

We have exposure to market risk for changes in interest rates, including the interest rate risk relating to our variable rate Tarrytown, New York lease (as described in Part II, Item 7. "Management's Discussion and Analysis of Financial Condition and Results of Operations - Liquidity and Capital Resources - Tarrytown, New York Leases"). Our interest rate exposure is offset by our investments in marketable securities. We continue to monitor our interest rate risk and may utilize derivative instruments and/or other strategies in the future to further mitigate our interest rate exposure.

Credit Quality Risk

We have an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and concentration and diversification. Nonetheless, deterioration of the credit quality of an investment security subsequent to purchase may subject us to the risk of not being able to recover the full principal value of the security. In 2023, 2022, and 2021, we did not record any charges for credit-related impairments of our available-for-sale debt securities.

We are subject to credit risk associated with the receivables due from our collaborators, including Bayer and Sanofi. We are also subject to credit risk in connection with trade accounts receivable due from our customers from our product sales. We have contractual payment terms with each of our collaborators and customers. We also monitor financial performance and credit worthiness so that we can properly assess and respond to any changes in collaborator and/or customer credit profiles. In 2023, 2022, and 2021, we did not recognize any charges for write-offs and allowances of accounts receivable related to credit risk for our collaborators or customers. As of December 31, 2023, two customers accounted on a combined basis for 83% of our net trade accounts receivables.

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Foreign Exchange Risk

As discussed further above, our collaborators market certain products outside the United States, and we share in profits and losses with these collaborators from commercialization of products. In addition, pursuant to the applicable terms of the agreements with our collaborators, we also share in certain worldwide development expenses incurred by our collaborators.

We also incur worldwide development expenses for clinical products we are developing independently, incur expenses outside the United States in connection with our international operations, and, effective July 1, 2022, market Libtayo outside the United States as a result of obtaining worldwide rights to Libtayo under an A&R IO LCA with Sanofi.

Therefore, significant changes in foreign exchange rates of the countries outside the United States where our products are sold, where development expenses are incurred by us or our collaborators, or where we incur operating expenses may impact our operating results and financial condition. As sales outside the United States continue to grow, and as we expand our international operations, we will continue to assess potential steps, including foreign currency hedging and other strategies, to mitigate our foreign exchange risk.

Market Price Risk

We are exposed to price risk on equity securities included in our investment portfolio. Our investments include equity securities of companies with which we have entered into collaboration arrangements. Changes in the fair value of our equity investments are included in Other income (expense), net on the Statements of Operations. We recorded $237.8 million and $39.8 million of net unrealized losses on equity securities in Other income (expense), net in 2023 and 2022, respectively.

Item 8. Financial Statements and Supplementary Data

The information required by this Item is set forth beginning on page F-1 of this report and is incorporated herein by reference.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

None.

Item 9A. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and principal financial officer, conducted an evaluation of the effectiveness of our disclosure controls and procedures (as such term is defined in Rules 13a-15(e) or 15d-15(e) under the Securities Exchange Act of 1934, as amended (the "Exchange Act")), as of the end of the period covered by this Annual Report on Form 10-K. Based on this evaluation, our principal executive officer and principal financial officer each concluded that, as of the end of such period, our disclosure controls and procedures were effective in ensuring that information required to be disclosed by us in the reports that we file or submit under the Exchange Act is recorded, processed, summarized, and reported on a timely basis, and is accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate to allow timely decisions regarding required disclosures.

Management's Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) or 15d-15(f) under the Exchange Act. Our management conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2023 using the framework in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on that evaluation, our management has concluded that our internal control over financial reporting was effective as of December 31, 2023. The effectiveness of the Company's internal control over financial reporting as of December 31, 2023 has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report which appears under Part IV, Item 15.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, 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.

Changes in Internal Control over Financial Reporting

There has been no change in our internal control over financial reporting (as such term is defined in Rules 13a-15(f) or 15d-15(f) under the Exchange Act) during the quarter ended December 31, 2023 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

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Inherent Limitations on Effectiveness of Controls

Our management, including our principal executive officer and principal financial officer, does not expect that our disclosure controls and procedures or internal controls over financial reporting will prevent all errors and all fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the system are met and cannot detect all deviations. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud or deviations, if any, within the company have been detected. Projections of any evaluation of effectiveness to future periods are subject to the risks that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Item 9B. Other Information

As disclosed in the table below, during the three months ended December 31, 2023, certain of our directors and/or executive officers adopted plans for trading arrangements intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) of the Exchange Act.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Not applicable.

PART III

Item 10. Directors, Executive Officers and Corporate Governance

The information required by this item (other than the information set forth in the next paragraph in this Item 10) will be included in our definitive proxy statement with respect to our 2024 Annual Meeting of Shareholders to be filed with the SEC, and is incorporated herein by reference.

We have adopted a code of business conduct and ethics that applies to our officers, directors, and employees. The full text of our code of business conduct and ethics can be found on our website (http://www.regeneron.com) under the "Governance" heading on the "Investors & Media" page. We may satisfy the disclosure requirements under Item 5.05 of Form 8-K regarding an amendment to, or a waiver from, a provision of our code of business conduct and ethics that applies to our principal executive officer, principal financial officer, principal accounting officer, or controller, or persons performing similar functions, by posting such information on our website where it is accessible through the same link noted above.

Item 11. Executive Compensation

The information called for by this item will be included in our definitive proxy statement with respect to our 2024 Annual Meeting of Shareholders to be filed with the SEC, and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions, and Director Independence

Item 14. Principal Accountant Fees and Services

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PART IV

Item 15. Exhibits and Financial Statement Schedules

(a)1. Financial Statements

The consolidated financial statements filed as part of this report are listed on the Index to Financial Statements on page F-1.

2. Financial Statement Schedules

All schedules for which provision is made in the applicable accounting regulations of the SEC are not required under the related instructions or are inapplicable and, therefore, have been omitted.

3. Exhibits

Exhibit Number Description

4.4 Form of 1.750% Senior Note due 2030 (included in Exhibit 4.3).

4.5 Form of 2.800% Senior Note due 2050 (included in Exhibit 4.3).

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21.1 Subsidiaries of the Registrant.

97.1 Clawback Policy.

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_______

+ Indicates a management contract or compensatory plan or arrangement.

Item 16. Form 10-K Summary

None.

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

REGENERON PHARMACEUTICALS, INC.

Date: February 5, 2024 By: /s/ LEONARD S. SCHLEIFER

Leonard S. Schleifer, M.D., Ph.D.

President and Chief Executive Officer

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POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Leonard S. Schleifer and Christopher Fenimore, and each of them, his or her true and lawful attorney-in-fact and agent, with the full power of substitution and resubstitution, for him or her and in his or her name, place, and stead, in any and all capacities therewith, to sign any and all amendments to this Annual Report on Form 10-K, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto each said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that each said attorney-in-fact and agent, or either of them, or their or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated:

Signature Title Date

Leonard S. Schleifer, M.D., Ph.D.

Robert E. Landry

Christopher Fenimore

George D. Yancopoulos, M.D., Ph.D.

/s/ BONNIE L. BASSLER Director February 5, 2024

Bonnie L. Bassler, Ph.D.

/s/ MICHAEL S. BROWN Director February 5, 2024

Michael S. Brown, M.D.

/s/ N. ANTHONY COLES Director February 5, 2024

N. Anthony Coles, M.D.

/s/ JOSEPH L. GOLDSTEIN Director February 5, 2024

Joseph L. Goldstein, M.D.

/s/ KATHRYN GUARINI Director February 5, 2024

Kathryn Guarini, Ph.D.

/s/ CHRISTINE A. POON Director February 5, 2024

Christine A. Poon

/s/ ARTHUR F. RYAN Director February 5, 2024

Arthur F. Ryan

/s/ DAVID P. SCHENKEIN Director February 5, 2024

David P. Schenkein, M.D.

/s/ GEORGE L. SING Director February 5, 2024

George L. Sing

/s/ CRAIG B. THOMPSON Director February 5, 2024

Craig B. Thompson, M.D.

/s/ HUDA Y. ZOGHBI Director February 5, 2024

Huda Y. Zoghbi, M.D.

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REGENERON PHARMACEUTICALS, INC.

INDEX TO FINANCIAL STATEMENTS

Page Numbers

Report of Independent Registered Public Accounting Firm (PCAOB ID 238) F-2

Consolidated Balance Sheets as of December 31, 2023 and 2022 F-4

Notes to Consolidated Financial Statements F-9 to F-46

F-1

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Report of Independent Registered Public Accounting Firm

To the Board of Directors and Stockholders of Regeneron Pharmaceuticals, Inc.

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of Regeneron Pharmaceuticals, Inc. and its subsidiaries (the "Company") as of December 31, 2023 and 2022, and the related consolidated statements of operations and comprehensive income, of stockholders' equity and of cash flows for each of the three years in the period ended December 31, 2023, including the related notes (collectively referred to as the "consolidated financial statements").We also have audited the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control - Integrated Framework(2013)issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidatedfinancial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Basis for Opinions

The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in Management's Report on Internal Control over Financial Reporting appearing under Item 9A. Our responsibility is to express opinions on the Company's consolidated financial statements and on the Company's internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidatedfinancial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

Definition and Limitations of Internal Control over Financial Reporting

A company's internal control over financial reporting is a process designed 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. A company's internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company's assets that could have a material effect on the financial statements.

F-2

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Critical Audit Matters

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that (i) relates to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Reserve for an Uncertain Tax Position

As described in Notes 1 and 15 to the consolidated financial statements, the Company's reserves for uncertain tax positions were $696.4 million as of December 31, 2023. A reserve for an individual uncertain tax position represents a portion of the consolidated balance. The Company recognizes the financial statement effects of a tax position when management's assessment is that there is more than a 50% probability that the position will be sustained upon examination by a taxing authority based upon its technical merits. Uncertain tax positions are recorded based upon certain recognition and measurement criteria. Management re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, and changes in facts or circumstances related to a tax position. The Company adjusts the amount of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain tax positions.

The principal considerations for our determination that performing procedures relating to the reserve for an uncertain tax position is a critical audit matter are (i) the significant judgment by management when determining the reserve for the uncertain tax position; (ii) a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management's determination of the reserve for the uncertain tax position; (iii) the assessment and evaluation of audit evidence available to support the reserve for the uncertain tax position is complex, and (iv) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the recognition of reserves for uncertain tax positions. These procedures also included, among others, (i) testing the information used in the calculation of the reserve for the individual uncertain tax position, such as international and federal filing positions, and the related final tax returns; (ii) testing the calculation of the reserve for the uncertain tax position; and (iii) evaluating management's assessment of the technical merits of tax positions and estimates of the amount of tax benefit expected to be sustained, as well as the likelihood of the possible outcome. Professionals with specialized skills and knowledge were used to assist in evaluating the technical merits and the tax benefit expected to be sustained and the application of relevant tax laws.

/s/ PricewaterhouseCoopers LLP

Florham Park, New Jersey

February 5, 2024

We have served as the Company’s auditor since 1989.

F-3

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REGENERON PHARMACEUTICALS, INC.

CONSOLIDATED BALANCE SHEETS

(In millions, except per share data)

December 31,

ASSETS

Current assets:

Prepaid expenses and other current assets 386.6 411.2

Property, plant, and equipment, net 4,146.4 3,763.0

LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:

Accrued expenses and other current liabilities 2,357.9 2,074.2

Commitments and contingencies

Stockholders' equity:

Accumulated other comprehensive loss (80.9) (238.8)

Total liabilities and stockholders' equity $ 33,080.2 $ 29,214.5

The accompanying notes are an integral part of the financial statements.

F-4

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REGENERON PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME

(In millions, except per share data)

Year Ended December 31,

Statements of Operations

Revenues:

Expenses:

Acquired in-process research and development 186.1 255.1 48.0

Cost of collaboration and contract manufacturing 883.7 760.4 664.4

Other operating (income) expense, net (2.1) (89.9) (45.6)

Other income (expense):

Weighted average shares outstanding - basic 106.7 107.1 105.7

Weighted average shares outstanding - diluted 113.7 113.5 112.2

Statements of Comprehensive Income

Other comprehensive income (loss), net of tax:

Unrealized gain (loss) on debt securities 158.2 (213.6) (56.4)

Loss on foreign currency translation (0.3) — —

Unrealized gain on cash flow hedges — 1.0 0.9

The accompanying notes are an integral part of the financial statements.

F-5

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REGENERON PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY

(In millions)

Shares Amount Shares Amount Shares Amount

Repurchases of Common Stock — — — — — — — (3.1) (1,655.0) (1,655.0)

Stock-based compensation charges — — — — 599.2 — — — — 599.2

Other comprehensive loss, net of tax — — — — — — (55.5) — — (55.5)

Repurchases of Common Stock — — — — — — — (3.3) (2,099.8) (2,099.8)

Stock-based compensation charges — — — — 737.8 — — — — 737.8

Other comprehensive loss, net of tax — — — — — — (212.6) — — (212.6)

F-6

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CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (continued)

Shares Amount Shares Amount Shares Amount

Repurchases of Common Stock — — — — — — — (3.0) (2,214.6) (2,214.6)

Stock-based compensation charges — — — — 894.3 — — — — 894.3

Other comprehensive income, net of tax — — — — — — 157.9 — — 157.9

The accompanying notes are an integral part of the financial statements.

F-7

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REGENERON PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In millions)

Year Ended December 31,

Cash flows from operating activities:

Losses (gains) on marketable and other securities, net 266.4 36.8 (387.0)

Changes in assets and liabilities:

(Increase) decrease in accounts receivable (338.8) 707.8 (1,927.4)

Increase in prepaid expenses and other assets (120.1) (148.6) (240.7)

Increase (decrease) in deferred revenue 37.9 32.4 (120.2)

Cash flows from investing activities:

Sales or maturities of marketable and other securities 9,442.2 5,550.5 2,215.3

Payments for Libtayo intangible asset (207.8) (1,026.8) —

Acquisitions, net of cash acquired (54.9) (230.3) —

Cash flows from financing activities:

Supplemental disclosure of cash flow information

Cash paid for interest (net of amounts capitalized) $ 73.1 $ 53.7 $ 55.8

The accompanying notes are an integral part of the financial statements.

F-8

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REGENERON PHARMACEUTICALS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1. Business Overview and Summary of Significant Accounting Policies

Organization and Business

Regeneron Pharmaceuticals, Inc. and its subsidiaries ("Regeneron," "Company," "we," "us," and "our") is a fully integrated biotechnology company that invents, develops, manufactures, and commercializes medicines for people with serious diseases. The Company's products and product candidates in development are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, hematologic conditions, infectious diseases, and rare diseases. The Company's research and development efforts have led to eleven products that have received marketing approval by the U.S. Food and Drug Administration ("FDA"). In addition, REGEN-COV® was authorized under an Emergency Use Authorization ("EUA") from November 2020 until January 2022 when the EUA was revised to exclude its use in geographic regions where infection or exposure is likely due to a variant that is not susceptible to the treatment; as a result, REGEN-COV is not currently authorized for use in any U.S. states, territories, or jurisdictions. The Company is a party to collaboration agreements to develop and commercialize, as applicable, certain products and product candidates (see Note 3).

The Company operates in one business segment, which includes all activities related to the discovery, development, and commercialization of medicines for serious diseases. The Company's business is subject to certain risks including, but not limited to, uncertainties relating to conducting research activities, product development, obtaining regulatory approvals, competition, and obtaining and enforcing patents.

Basis of Presentation

The consolidated financial statements include the accounts of Regeneron and its wholly-owned subsidiaries. Intercompany balances and transactions are eliminated in consolidation.

Certain reclassifications have been made to prior period amounts to conform with the current period's presentation.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Concentration of Credit Risk

Financial instruments which potentially expose the Company to concentrations of credit risk consist of cash, cash equivalents, certain investments, and accounts receivable. In accordance with the Company's policies, the Company mandates asset diversification and monitors exposure with its counterparties.

Concentrations of credit risk with respect to collaborator (see Note 3) and customer accounts receivable are significant. As of December 31, 2023 and 2022, two individual customers accounted for83% and 86% of the Company's net trade accounts receivable balances, respectively. The Company has contractual payment terms with each of its collaborators and customers, and the Company monitors their financial performance and credit worthiness so that it can properly assess and respond to any changes in their credit profile. As of December 31, 2023 and 2022, there were no write-offs and allowances of accounts receivable related to credit risk for the Company's collaborators or customers.

Significant Accounting Policies

Cash and Cash Equivalents

The Company considers all highly liquid debt instruments with a maturity of three months or less when purchased to be cash equivalents. The carrying amount reported in the Consolidated Balance Sheet for cash and cash equivalents approximates its fair value.

Debt and Equity Securities

The Company has an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and diversification. The Company invests its cash primarily in debt securities. The Company considers its investments in debt securities to be "available-for-sale," as defined by authoritative guidance issued by the Financial Accounting Standards Board ("FASB"). These assets are carried at fair value and the unrealized gains and losses are included in accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale debt securities are included in other income

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(expense), net. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss).

The Company also has investments in equity securities that are carried at fair value with changes in fair value recognized within other income (expense), net. The Company has elected to measure certain equity investments it holds that do not have readily determinable fair values at cost less impairment, if any, and adjusts for observable price changes in orderly transactions for identical or similar investments of the same issuer within other income (expense), net.

Accounts Receivable

The Company's trade accounts receivable arise from product sales and represent amounts due from its customers. In addition, the Company records accounts receivable arising from its collaboration and licensing agreements. The Company monitors the financial performance and credit worthiness of its counterparties so that it can properly assess and respond to changes in their credit profile. The Company provides allowances against receivables for estimated losses, if any, that may result from a counterparty's inability to pay. Amounts determined to be uncollectible are written-off against the allowance.

Inventories

Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first-out, or FIFO, method.

The Company capitalizes inventory costs associated with the Company's products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval.

The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale or has a cost basis in excess of its estimated realizable value, and writes down such inventories as appropriate. In addition, the Company's products are subject to strict quality control and monitoring which the Company performs throughout the manufacturing process. If certain batches or units of product no longer meet quality specifications or become obsolete due to expiration, the Company records a charge to write down such inventory to its estimated realizable value.

Property, Plant, and Equipment

Property, plant, and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated on a straight-line basis over the estimated useful lives of the assets. Leasehold improvements are amortized over the shorter of the estimated useful lives of the assets or the remaining lease term. Costs of construction of certain long-lived assets include capitalized interest, which is amortized over the estimated useful life of the related asset. Expenditures for maintenance and repairs which do not materially extend the useful lives of the assets are charged to expense as incurred. The cost and accumulated depreciation or amortization of assets retired or sold are removed from the respective accounts, and any gain or loss is recognized within income from operations. The estimated useful lives of property, plant, and equipment are as follows:

Building and improvements 10–50 years

Laboratory and other equipment 3–10 years

Furniture and fixtures 5 years

The Company periodically assesses the recoverability of long-lived assets, such as property, plant, and equipment, and evaluates such assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.

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Leases

The Company determines if an arrangement is a lease considering whether there is an identified asset and the contract conveys the right to control its use. Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company may include options to extend or terminate a lease within the lease term when it is reasonably certain that it will exercise that option. The Company accounts for lease components (e.g., rental payments) separately from non-lease components (e.g., common area maintenance costs).

Lease liabilities are recognized at the lease commencement date based on the present value of the remaining lease payments, discounted using the rate implicit in the lease. For leases where an implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on information available at the lease commencement date to determine the present value of future lease payments. Lease expense for operating leases is recognized on a straight-line basis over the expected lease term.

Acquisitions

The Company makes a determination whether a transaction should be accounted for as a business combination or as an asset acquisition. In a business combination, the acquisition method of accounting generally requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values. Amounts allocated to acquired in-process research and development are capitalized as indefinite-lived intangible assets. Any excess of the purchase price (consideration transferred) over the fair values of net assets acquired is recorded as goodwill. In a business combination, contingent consideration obligations are recorded at fair value as of the acquisition date and remeasured each subsequent reporting period until the contingencies have been resolved, with any changes in fair value recorded in Other operating (income) expense, net.

If it is determined that the assets acquired do not meet the definition of a business, or if substantially all of the fair value of the assets acquired are concentrated in a single identifiable asset, then the transaction is accounted for as an asset acquisition rather than a business combination. In an asset acquisition, assets acquired are recorded at cost, goodwill is not recognized, and acquired in-process research and development with no alternative future use is charged to expense.

Intangible Assets

Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in connection with an asset acquisition are recorded at cost.

Indefinite-lived intangible assets are subject to impairment testing until completion or abandonment of the associated research and development efforts. Definite-lived intangible assets are amortized to Cost of goods sold over the estimated useful lives of the assets based on the pattern in which the economic benefits of the intangible assets are consumed; if that pattern cannot be reliably determined, a straight-line basis is used.

Intangible assets are reviewed for recoverability whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. If an indicator of impairment exists, the Company compares the projected undiscounted cash flows to be generated by the asset to the intangible asset's carrying amount. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, the intangible asset is written down to its fair value in the period in which the impairment occurs.

Product Revenue

Revenue from product sales is recognized at a point in time when the Company's customer is deemed to have obtained control of the product, which generally occurs upon receipt or acceptance by its customer.

The amount of revenue the Company recognizes from product sales may vary due to rebates, chargebacks, and discounts provided under governmental and other programs, distribution-related fees, and other sales-related deductions. In order to determine the transaction price, the Company estimates, utilizing the expected value method, the amount of variable consideration to which the Company will be entitled. This estimate is based upon contracts with customers, healthcare providers, payors, and government agencies, statutorily-defined discounts applicable to government-funded programs, historical experience, estimated payor mix,

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and other relevant factors. The Company reviews its estimates of rebates, chargebacks, and other applicable provisions each period and records any necessary adjustments in the current period's net product sales.

•Rebates: The Company's rebates include amounts paid to managed care organizations, group purchasing organizations, state Medicaid programs, and other rebate programs. The Company estimates reductions to product sales for each type of rebate and records an allowance for rebates in the same period in which the related product sales are recognized. The Company's liability for rebates consists of estimates for claims related to the current and prior periods that have not been paid and estimates for claims that will be made related to product that exists in the distribution channel at the end of the period.

•Chargebacks and Discounts: The Company's reserves related to discounted pricing to eligible physicians, Veterans' Administration ("VA"), Public Health Services, and others (collectively "qualified healthcare providers") represent the Company's estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices the Company charges to its customers (i.e., distributors and specialty pharmacies). The Company's customers charge the Company for the difference between what they pay for the products and the discounted selling price to the qualified healthcare providers. The Company estimates reductions to product sales for each type of chargeback and records an allowance for chargebacks in the same period that the related product sales are recognized. The Company's reserve for chargebacks consists of amounts for which it expects to issue credit based on expected sales by its customers to qualified healthcare providers and chargebacks that customers have claimed but for which the Company has not yet issued credit.

•Distribution-Related Fees: The Company has written contracts with its customers that include terms for distribution-related fees. The Company estimates and records distribution and related fees due to its customers generally based on gross sales.

•Other Sales-Related Deductions: The Company's other sales-related deductions include co-pay assistance programs and product returns. The Company estimates and records other sales-related deductions generally based on gross sales, written contracts, and other relevant factors.

Consistent with industry practice, the Company generally offers its customers a limited right to return product purchased directly from the Company, which is principally based upon the product's expiration date. Product returned is generally not resalable given the nature of the Company's products and method of administration. The Company develops estimates for product returns based upon historical experience, shelf life of the product, and other relevant factors. The Company monitors product supply levels in the distribution channel, as well as sales by its customers, using product-specific data provided by its customers. If necessary, the Company's estimates of product returns may be adjusted in the future based on actual returns experience, known or expected changes in the marketplace, or other factors.

Collaborative Arrangements

The Company has entered into various collaborative arrangements to research, develop, manufacture, and commercialize products and/or product candidates. Although each of these arrangements is unique in nature, such arrangements involve a joint operating activity where both parties are active participants in the activities of the collaboration and exposed to significant risks and rewards dependent on the commercial success of the activities.

In arrangements where the Company does not deem its collaborator to be its customer, payments to and from its collaborator are presented in the Company's statement of operations based on the nature of our business operations, the nature of the arrangement, including the contractual terms, and the nature of the payments. In general, the presentation of such amounts is summarized below.

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Nature/Type of Payment Statement of Operations Presentation

Reimbursement for manufacturing of commercial supplies Collaboration revenue

Royalties and/or sales-based milestones earned Collaboration revenue

In agreements involving multiple goods or services promised to be transferred to the Company's collaborator, the Company assesses, at the inception of the contract, whether each promise represents a separate obligation (i.e., is "distinct"), or whether such promises should be combined as a single unit of account. When the Company has a combined unit of account which includes a license and providing research and development services to its collaborator, recognition of up-front payments and development milestones earned from its collaborator is deferred (as a liability) and recognized over the development period (i.e., over time) typically using an input method on the basis of the Company's research and development costs incurred relative to the total expected cost which determines the extent of the Company's progress toward completion. The Company reviews its estimates each period and makes revisions to such estimates as necessary.

When the Company is entitled to reimbursement of all or a portion of the expenses (e.g., research and development expenses) that it incurs under a collaboration, it records those reimbursable amounts in the period in which such costs are incurred.

If the Company's collaborator performs research and development work or commercialization-related activities and the parties share the related costs, the Company also recognizes, as expense (e.g., research and development expense or selling, general, and administrative expense, as applicable) in the period when its collaborator incurs such expenses, the portion of the collaborator's expenses that the Company is obligated to reimburse. The Company's collaborators provide the Company with estimated expenses for the most recent fiscal quarter. The estimates are revised, if necessary, in subsequent periods if actual expenses differ from those estimates.

•supplies commercial product to its collaborator, the Company may be reimbursed for its manufacturing costs as commercial product is shipped to the collaborator (however, recognition of such cost reimbursements may be deferred until the product is sold by the Company's collaborator to third-party customers);

•shares in any profits or losses arising from the commercialization of such products, the Company records its share of the variable consideration, representing net product sales less cost of goods sold and shared commercialization and other expenses, in the period in which such underlying sales occur and costs are incurred by the collaborator;

•receives royalties and/or sales-based milestone payments from its collaborator, the Company recognizes such amounts in the period earned.

The Company's collaborators provide it with estimates of product sales and the Company's share of profits or losses, as applicable, for each quarter. The estimates are revised, if necessary, in subsequent periods if the Company's actual share of profits or losses differ from those estimates.

Research and Development Expenses

Research and development expenses include costs attributable to the conduct of research and development programs, including the cost of salaries, payroll taxes, employee benefits, materials, supplies, depreciation on and maintenance of research equipment,

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costs related to research collaboration and licensing agreements, clinical trial expenses, the cost of services provided by outside contractors, including services related to the Company's clinical trials, the cost of manufacturing drug for use in research and development, amounts that the Company is obligated to reimburse to collaborators for research and development expenses that they incur, and the allocable portions of facility costs. Costs associated with research and development are expensed.

For each clinical trial that the Company conducts, certain clinical trial costs are expensed immediately, while others are expensed over time based on the expected total number of patients in the trial, the rate at which patients enter and remain in the trial, and/or the period over which clinical investigators, contract research organizations ("CROs"), or other third-party service providers are expected to provide services. In the event of early termination of a clinical trial, the Company accrues and recognizes expenses in an amount based on its estimate of the remaining noncancelable obligations associated with the winding-down of the clinical trial, including any applicable penalties.

Stock-based Compensation

The Company recognizes stock-based compensation expense for equity grants under the Company's long-term incentive plans (including stock options, restricted stock awards, and restricted stock units (both time-based and performance-based)) to employees and non-employee members of the Company's board of directors (as applicable) based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Stock-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. This estimate is revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. In addition, the Company reassesses its forfeiture rate assumptions at least annually, considering both historical forfeiture experience and an estimate of future forfeitures for currently outstanding unvested awards.

The Company uses the Black-Scholes model to compute the estimated fair value of stock option awards. Additionally, the Company uses a Monte Carlo simulation to compute the estimated fair value of performance-based restricted stock units that are subject to vesting based on the Company’s attainment of pre-established criteria that include a market condition.

For performance-based restricted stock units that contain a performance condition, the Company recognizes stock-based compensation expense if and when the Company determines that it is probable the performance condition will be achieved (based on the number of shares expected to be vested and issued). The Company reassesses the probability of achievement at each reporting period and adjusts compensation cost, as necessary. If there are any changes in the Company's probability assessment, the Company recognizes a cumulative catch-up adjustment in the period of the change in estimate, with the remaining unrecognized expense recognized prospectively over the remaining requisite service period. If the Company subsequently determines that the performance criteria are not met or are not expected to be met, any amounts previously recognized as compensation expense are reversed in the period when such determination is made.

Income Taxes

The provision for income taxes includes U.S. federal, state, local, and foreign taxes. Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been included in the financial statements or tax returns, including deferred tax assets and liabilities for expected amounts of global intangible low-taxed income ("GILTI") inclusions. Deferred tax assets and liabilities are determined as the difference between the tax basis of assets and liabilities and their respective financial reporting amounts ("temporary differences") at enacted tax rates in effect for the years in which the differences are expected to reverse. A valuation allowance is established for deferred tax assets for which it is more likely than not that some portion or all of the deferred tax assets will not be realized.

The Company recognizes the financial statement effects of a tax position when management's assessment is that there is more than a 50% probability that the position will be sustained upon examination by a taxing authority based upon its technical merits. Uncertain tax positions are recorded based upon certain recognition and measurement criteria. The Company re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, information obtained during in-process audit activities, and changes in facts or circumstances related to a tax position. The Company adjusts the amount of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain tax positions. The Company recognizes interest and penalties related to income tax matters in income tax expense.

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Per Share Data

Basic net income per share is computed by dividing net income by the weighted average number of shares of Common Stock and Class A Stock outstanding. Net income per share is presented on a combined basis, inclusive of Common Stock and Class A Stock outstanding, as each class of stock has equivalent economic rights. Basic net income per share excludes restricted stock until vested. Diluted net income per share includes the potential dilutive effect of common stock equivalents as if such securities were converted or exercised during the period, when the effect is dilutive. Common stock equivalents include outstanding stock options and unvested restricted stock under the Company's long-term incentive plans, which are included under the treasury stock method when dilutive.

Recently Issued Accounting Standards

In November 2023, the FASB issued Accounting Standards Update No. 2023-07, Segment Reporting - Improvements to Reportable Segment Disclosures. The amendments require disclosure of incremental segment information on an annual and interim basis. The amendments also require companies with a single reportable segment to provide all disclosures required by this amendment and all existing segment disclosures in Accounting Standards Codification 280, Segment Reporting. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The Company does not expect the adoption of the amendments to have a significant impact on its financial statements.

In December 2023, the FASB issued Accounting Standards Update No. 2023-09, Income Taxes - Improvements to Income Tax Disclosures. The amendments require (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. The amendments are effective for annual periods beginning after December 15, 2024. The Company does not expect the adoption of the amendments to have a significant impact on its financial statements.

2. Product Sales

Net product sales consist of the following:

Year Ended December 31,

EYLEA® HD U.S. $ 165.8 $ — $ —

REGEN-COV®(c) U.S. — — 5,828.0

ARCALYST®(d) U.S. — — 2.2

(b) Rest of world ("ROW")

As of December 31, 2023 and 2022, the Company had $3.888 billion and $3.586 billion, respectively, of trade accounts receivable that were recorded within Accounts receivable, net.

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The Company had product sales to certain customers that accounted for more than 10% of total gross product revenue for each of the years ended December 31, 2023, 2022, and 2021. Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows:

Year Ended December 31,

Besse Medical, a subsidiary of Cencora, Inc. 51 % 55 % 30 %

McKesson Corporation 25 % 28 % 18 %

U.S. government * * 43 %

Revenue from product sales is recorded net of applicable provisions for rebates, chargebacks, and discounts, distribution-related fees, and other sales-related deductions. Accruals for chargebacks and discounts are recorded as a direct reduction to accounts receivable. Accruals for rebates, distribution-related fees, and other sales-related deductions are recorded within accrued liabilities. The following table summarizes the provisions, and credits/payments, for sales-related deductions.

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3. Collaboration, License, and Other Agreements

a. Sanofi

Amounts recognized in the Company's Statements of Operations in connection with its collaborations with Sanofi are detailed below:

Statement of Operations Classification Year Ended December 31,

Antibody:

Sales-based milestones earned Collaboration revenue $ 50.0 $ 100.0 $ 50.0

Other Collaboration revenue $ — $ 28.7 $ —

Immuno-oncology(a):

Reimbursement of R&D expenses Reduction of R&D expense $ — $ 42.7 $ 85.1

Antibody

The Company is party to a global, strategic collaboration with Sanofi to research, develop, and commercialize fully human monoclonal antibodies (the "Antibody Collaboration"), which currently consists of Dupixent® (dupilumab), Kevzara® (sarilumab), and itepekimab.

Under the terms of the Antibody License and Collaboration Agreement (the "LCA"), Sanofi is generally responsible for funding 80% to 100% of agreed-upon development costs. The Company is obligated to reimburse Sanofi for 30% to 50% of worldwide development expenses that were funded by Sanofi based on the Company's share of collaboration profits from commercialization of collaboration products. Under the terms of the LCA, the Company was required to apply 10% of its share of the profits from the Antibody Collaboration in any calendar quarter to reimburse Sanofi for these development costs. On July 1, 2022, an amendment to the LCA became effective, pursuant to which the percentage of the Company's share of profits used to reimburse Sanofi for such development costs increased from 10% to 20%. A portion of the value associated with the increase in reimbursement percentage was deemed to be contingent consideration attributable to the Company's acquisition of the Libtayo (cemiplimab) rights described within the "Immuno-Oncology" section below; this portion is recorded as an increase to the Libtayo intangible asset over time as the Company repays such development costs to Sanofi. The Company's contingent reimbursement obligation to Sanofi under the Antibody Collaboration was approximately $2.330 billion as of December 31, 2023.

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Sanofi leads commercialization activities for products under the Antibody Collaboration, subject to the Company's right to co-commercialize such products. The Company co-commercializes Dupixent in the United States and in certain countries outside the United States. The parties equally share profits from sales within the United States. The parties share profits outside the United States on a sliding scale based on sales starting at 65% (Sanofi)/35% (Regeneron) and ending at 55% (Sanofi)/45% (Regeneron).

In addition to profit sharing, the Company was entitled to receive sales milestone payments from Sanofi. In 2023, the Company earned the final $50.0 million sales-based milestone from Sanofi, upon aggregate annual sales of antibodies outside the United States (including Praluent, which was previously included in the LCA) exceeding $3.0 billion on a rolling twelve-month basis. In 2022, the Company earned two $50.0 million sales-based milestones from Sanofi, upon aggregate annual sales of antibodies outside the United States (including Praluent) exceeding $2.0 billion and $2.5 billion, respectively, on a rolling twelve-month basis. In 2021, the Company earned a $50.0 million sales-based milestone from Sanofi, upon aggregate annual sales of antibodies outside the United States (including Praluent) exceeding $1.5 billion, on a rolling twelve-month basis.

The Company's significant promised goods and services in connection with the Antibody Collaboration consist of providing research and development services, including the manufacturing of clinical supplies, and providing commercial-related services, including the manufacturing of commercial supplies. The Company recognizes amounts in connection with the Antibody Collaboration based on the amount it has the right to invoice and such amount corresponds directly with the Company's performance to date.

The following table summarizes contract balances in connection with the Company's Antibody Collaboration with Sanofi:

As of December 31,

Immuno-Oncology

The Company was previously a party to a collaboration with Sanofi for antibody-based cancer treatments in the field of immuno-oncology (the "IO Collaboration"). The IO Collaboration was governed by an Amended and Restated Immuno-oncology Discovery and Development Agreement ("Amended IO Discovery Agreement"), and an Immuno-oncology License and Collaboration Agreement ("IO License and Collaboration Agreement"). In connection with the execution of the original Immuno-oncology Discovery and Development Agreement in 2015 ("2015 IO Discovery Agreement"), which was subsequently replaced by the Amended IO Discovery Agreement (as discussed below), Sanofi made a $265.0 million non-refundable up-front payment to the Company. Pursuant to the 2015 IO Discovery Agreement, the Company was to identify and validate potential immuno-oncology targets and develop therapeutic antibodies against such targets through clinical proof-of-concept.

Effective December 31, 2018, the Company and Sanofi entered into the Amended IO Discovery Agreement, which narrowed the scope of the existing discovery and development activities conducted by the Company under the 2015 IO Discovery Agreement to developing therapeutic bispecific antibodies targeting (i) BCMA and CD3 and (ii) MUC16 and CD3 through clinical proof-of-concept. During 2021, Sanofi did not exercise its options to license rights to these product candidates; as a result, the Company retains the exclusive right to develop and commercialize such product candidates and Sanofi will receive a royalty on sales (if any). In addition, the Company has no further obligations to develop drug product candidates under the Amended IO Discovery Agreement.

In connection with the execution of the IO License and Collaboration Agreement in 2015, Sanofi made a $375.0 million non-refundable up-front payment to the Company. Under the terms of the IO License and Collaboration Agreement, the parties were co-developing and co-commercializing Libtayo. The parties shared equally, on an ongoing basis, development and commercialization expenses for Libtayo. The Company had principal control over the development of Libtayo and led commercialization activities in the United States, while Sanofi led commercialization activities outside the United States. The parties shared equally in profits and losses in connection with the commercialization of Libtayo.

Recognition of the up-front payments received from Sanofi had been deferred (recorded within Other liabilities), and such amounts were being recognized over the remaining period in which the Company was obligated to perform development activities. During 2021, the Company updated its estimate of the total research and development costs expected to be incurred (which resulted in a change to the estimate of the stage of completion) in connection with the IO Collaboration, and, as a result, recorded a cumulative catch-up adjustment of $66.9 million as a reduction to other operating income.

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In connection with the Amended and Restated Immuno-oncology License and Collaboration Agreement with Sanofi (the "A&R IO LCA") described below, the remaining IO Collaboration Other liabilities balance of $241.0 million as of July 1, 2022 was recognized as a reduction to the intangible asset recorded in connection with the transaction during 2022.

Effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide under the A&R IO LCA. In connection with the A&R IO LCA, in 2022, the Company made a $900.0 million up-front payment to Sanofi, as well as a $100.0 million regulatory milestone payment. In addition, Sanofi was eligible to earn an aggregate of $100.0 million in Libtayo sales-based milestones under the terms of the A&R IO LCA, of which they earned $65.0 million in 2022 and $35.0 million in 2023. The Company also pays Sanofi an 11% royalty on net product sales of Libtayo through March 31, 2034. The transaction was accounted for as an asset acquisition and amounts paid to Sanofi in connection with obtaining the worldwide rights to Libtayo, including the up-front payment and any contingent consideration, are recorded as an intangible asset. See Note 8 for additional information related to the intangible asset.

In accordance with the Amended IO Discovery Agreement, the Company was obligated to reimburse Sanofi for half of the development costs it funded that were attributable to clinical development of product candidates from the Company's share of profits from commercialized IO Collaboration products. Under the A&R IO LCA, the amount of development costs incurred under the IO Collaboration for which the Company was obligated to reimburse Sanofi was $35.0 million as of the effective date of the A&R IO LCA, and the Company pays Sanofi a 0.5% royalty on net product sales of Libtayo until all such development costs have been reimbursed by Regeneron. The Company's contingent reimbursement obligation to Sanofi under the A&R IO LCA was approximately $28 million as of December 31, 2023.

b. Bayer

The Company is party to a license and collaboration agreement with Bayer for the global development and commercialization of EYLEA 8 mg (aflibercept 8 mg) and EYLEA (aflibercept) outside the United States. Agreed-upon development expenses incurred by the Company and Bayer are generally shared equally. The Company is also obligated to use commercially reasonable efforts to supply clinical and commercial bulk product.

Within the United States, the Company is responsible for commercialization and retains profits from such sales. Bayer is responsible for commercialization activities outside the United States, and the companies share equally in profits from such sales. In Japan, the Company was entitled to receive a tiered percentage of between 33.5% and 40.0% of EYLEA net product sales through 2021, and effective January 1, 2022, the companies share equally in profits from sales in Japan. The Company is obligated to reimburse Bayer out of its share of the collaboration profits for 50% of the agreed-upon development expenses that Bayer has incurred in accordance with a formula based on the amount of development expenses that Bayer has incurred and the Company's share of the collaboration profits, or at a faster rate at the Company's option. The Company's contingent reimbursement obligation to Bayer was approximately $293 million as of December 31, 2023.

Amounts recognized in the Company's Statements of Operations in connection with its Bayer collaboration are as follows:

Statement of Operations Classification Year Ended December 31,

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The following table summarizes contract balances in connection with the Company's Bayer collaboration:

As of December 31,

c. Alnylam

In 2019, the Company and Alnylam Pharmaceuticals, Inc. entered into a global, strategic collaboration to discover, develop, and commercialize RNA interference ("RNAi") therapeutics for a broad range of diseases by addressing therapeutic disease targets expressed in the eye and central nervous system ("CNS"), in addition to a select number of targets expressed in the liver. In connection with entering into the collaboration, the Company made an up-front payment of $400.0 million to Alnylam, and also purchased shares of Alnylam common stock for $400.0 million. For each program, the Company provides Alnylam with a specified amount of funding at program initiation and at lead candidate designation. Under the terms of the collaboration, the parties perform discovery research until designation of lead candidates. Following designation of a lead candidate, the parties may further advance such lead candidate under either a co-development/co-commercialization collaboration agreement (under which the parties are advancing ALN-APP and ALN-PNP, which are currently in clinical development) or a license agreement.

The initial target nomination and discovery period is five years (which may under certain situations automatically be extended for up to seven years in the aggregate) (the "Research Term"). In addition, the Company has the option to extend the Research Term for an additional five-year period for a research extension fee of $300.0 million.

During 2023, the Company paid a $100.0 million development milestone to Alnylam, which was recorded to Acquired in-process research and development expense, upon the achievement of specified proof-of-principle criteria for the ALN-APP program. Alnylam is eligible to receive an additional $100.0 million clinical proof-of-principle milestone in connection with an eye program.

Amounts recognized in the Company's Statements of Operations in connection with its Alnylam collaboration are as follows:

Statement of Operations Classification Year Ended December 31,

The following table summarizes contract balances in connection with the Company's Alnylam collaboration:

As of December 31,

Accrued expenses and other current liabilities $ 22.6 $ 7.4

d. Roche

The Company is a party to a collaboration agreement with Roche to develop, manufacture, and distribute the casirivimab and imdevimab antibody cocktail (known as REGEN-COV in the United States and RonapreveTM in other countries). Under the terms of the collaboration agreement, the parties jointly fund certain studies, and the Company has the right to distribute the product in the United States while Roche has the right to distribute the product outside the United States. The parties share gross profits from worldwide sales based on a pre-specified formula, depending on the amount of manufactured product supplied by each party to the market.

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Amounts recognized in the Company's Statements of Operations in connection with its Roche collaboration are as follows:

Statement of Operations Classification Year Ended December 31,

Other Collaboration revenue $ (13.3) $ — $ —

The following table summarizes contract balances in connection with the Company's Roche collaboration:

As of December 31,

Accounts receivable, net $ — $ 396.6

e. Intellia

In 2016, the Company entered into a license and collaboration agreement with Intellia Therapeutics, Inc. to advance CRISPR/Cas9 gene-editing technology for in vivo therapeutic development. The parties collaborate to conduct research for the discovery, development, and commercialization of new therapies, in addition to the research and technology development of the CRISPR/Cas9 platform.

Under the terms of the 2016 agreement, the parties agreed to a target selection process, whereby the Company may obtain exclusive rights in up to 10 targets to be chosen by the Company during the collaboration term, subject to various adjustments and limitations set forth in the agreement. Certain targets that either the Company or Intellia selects may be subject to a co-development and co-commercialization arrangement at the Company's option or Intellia’s option, as applicable. NTLA-2001, which is in clinical development, is subject to a co-development and co-commercialization arrangement pursuant to which Intellia will lead development and commercialization activities and the parties share an agreed-upon percentage of development expenses and profits (if commercialized).

REGN US Equity

REGN · 10-K · period ended 2023-12-31

Item 7. Management's Discussion and Analysis of Financial Condition and Results and Results of Operations

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

Item 8. Financial Statements and Supplementary Data

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A. Controls and Procedures

Item 9B. Other Information

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Item 10. Directors, Executive Officers and Corporate Governance

Item 11. Executive Compensation

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions, and Director Independence

Item 14. Principal Accountant Fees and Services

Item 15. Exhibits and Financial Statement Schedules

Item 16. Form 10-K Summary

REGN US Equity☆

REGN · 10-K · period ended 2023-12-31

Item 7. Management's Discussion and Analysis of Financial Condition and Results and Results of Operations

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

Item 8. Financial Statements and Supplementary Data

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A. Controls and Procedures

Item 9B. Other Information

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Item 10. Directors, Executive Officers and Corporate Governance

Item 11. Executive Compensation

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions, and Director Independence

Item 14. Principal Accountant Fees and Services

Item 15. Exhibits and Financial Statement Schedules

Item 16. Form 10-K Summary

REGN US Equity