Amphastar Pharmaceuticals, Inc.

**Note 1.**General

Amphastar Pharmaceuticals, Inc., a Delaware corporation (together with its subsidiaries, hereinafter referred to as the “Company”), is a biopharmaceutical company that focuses primarily on developing, manufacturing, marketing, and selling technically challenging generic and proprietary injectable, inhalation, and intranasal products, including products with high technical barriers to market entry. Additionally, the Company sells insulin active pharmaceutical ingredient, or API, products. Most of the Company’s products are used in hospital or urgent care clinical settings and are primarily contracted and distributed through group purchasing organizations and drug wholesalers. The Company’s insulin API products are sold to other pharmaceutical companies for use in their own products and are being used by the Company in the development of injectable pharmaceutical products. The Company’s over-the-counter inhalation product, Primatene MIST®, is primarily distributed through drug retailers.

The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company for the year ended December 31, 2024 and the notes thereto as filed with the Securities and Exchange Commission, or SEC, in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, have been condensed or omitted from the accompanying condensed consolidated financial statements. The accompanying year-end condensed consolidated balance sheet was derived from the audited financial statements. The accompanying interim financial statements are unaudited, but reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the Company’s consolidated financial position, results of operations, comprehensive income, stockholders’ equity, and cash flows for the periods presented. Unless otherwise noted, all such adjustments are of a normal, recurring nature. The Company’s results of operations, comprehensive income and cash flows for the interim periods are not necessarily indicative of the results of operations and cash flows that it may achieve in future periods.

Note 2. Summary of Significant Accounting Policies

Basis of Presentation

The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and are prepared in accordance with GAAP. All intercompany activity has been eliminated in the preparation of the condensed consolidated financial statements. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments, which are of a normal recurring nature, necessary to present fairly the consolidated financial position, results of operations, and cash flows of the Company.

The Company’s subsidiaries include: (1) International Medication Systems, Limited, or IMS, (2) Armstrong Pharmaceuticals, Inc., or Armstrong, (3) Amphastar Nanjing Pharmaceuticals Inc., or ANP, (4) Amphastar France Pharmaceuticals, S.A.S., or AFP, (5) Amphastar UK Ltd., or AUK, and (6) International Medication Systems (UK) Limited, or IMS UK.

Use of Estimates

The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. The principal accounting estimates include: fair value of financial instruments, allowance for credit losses, discounts, provision for chargebacks and rebates, provision for product returns, adjustment of inventory to its net realizable value, impairment of investments, long-lived and intangible assets and goodwill, litigation reserves, stock price volatility for share-based compensation expense, valuation allowances for deferred tax assets, and liabilities for uncertain income tax positions.

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Foreign Currency

The functional currency of the Company, its domestic subsidiaries, its Chinese subsidiary ANP, and its U.K. subsidiary, AUK, is the U.S. Dollar, or USD. ANP maintains its books of record in Chinese yuan. These books are remeasured into the functional currency of USD using the current or historical exchange rates. The resulting currency remeasurement adjustments and other transactional foreign currency exchange gains and losses are reflected in the Company’s condensed consolidated statements of operations.

The Company’s French subsidiary, AFP, maintains its books of record in euros. AUK’s subsidiary, IMS UK, maintains its books of record in British pounds. These local currencies have been determined to be the subsidiaries’ respective functional currencies. Activities in the statements of operations are translated to USD using average exchange rates during the period. Assets and liabilities are translated at the rate of exchange prevailing on the balance sheet date. Equity is translated at the prevailing rate of exchange at the date of the equity transactions. Translation adjustments are reflected in stockholders’ equity and are included as a component of other comprehensive income. The unrealized gains or losses of intercompany foreign currency transactions that are of a long-term investment nature are reported in other accumulated comprehensive income.

The unrealized gains and losses of intercompany foreign currency transactions that are of a long-term investment nature were a $0.1 million gain and a $4.0 million gain for the three and nine months ended September 30, 2025, respectively. For the three and nine months ended September 30, 2024, the unrealized gains and losses of intercompany foreign currency transactions that are of a long-term investment nature were a $1.4 million gain and a $0.4 million gain, respectively.

Comprehensive Income

The Company’s comprehensive income includes foreign currency translation gains and losses.

Advertising Expense

Advertising expenses, primarily associated with Primatene MIST®, are recorded as they are incurred, except for expenses related to the development of a major commercial or media campaign, which are expensed in the period in which the commercial or campaign is first presented, and are reflected as a component of selling, distribution and marketing in the Company’s condensed consolidated statements of operations. For the three and nine months ended September 30, 2025, advertising expenses were $2.6 million and $8.1 million, respectively. For the three and nine months ended September 30, 2024, advertising expenses were $2.5 million and $7.8 million, respectively.

Financial Instruments

The Company’s accompanying condensed consolidated balance sheets include the following financial instruments: cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued expenses, short-term borrowings, and long-term obligations. The Company considers the carrying amounts of current assets and liabilities on the condensed consolidated balance sheets to approximate the fair value of these financial instruments due to the short maturity of these items. The carrying value of the Company’s long-term obligations, with the exception of the convertible debt (see Note 13), approximates their fair value, as the stated borrowing rates are comparable to rates currently offered to the Company for instruments with similar maturities. The Company at times enters into interest rate swap contracts to manage its exposure to interest rate changes and its overall cost of long-term debt. The Company’s interest rate swap contracts exchange the variable interest rates for fixed interest rates.

Cash and Cash Equivalents

Cash and cash equivalents consist of cash, money market accounts, certificates of deposit and highly liquid investments with original maturities of three months or less.

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Investments

Investments as of September 30, 2025 and December 31, 2024 consisted of certificates of deposit and investment grade corporate, agency and municipal bonds with original maturity dates between three and nineteen months.

Restricted Cash

Restricted cash is collateral required for the Company to guarantee certain vendor payments in France. As of September 30, 2025 and December 31, 2024, the restricted cash balance was $0.2 million.

Restricted Short-Term Investments

Restricted short-term investments consist of certificates of deposit that are collateral for standby letters of credit to qualify for workers’ compensation self-insurance. The certificates of deposit have original maturities greater than three months, but less than one year. As of September 30, 2025 and December 31, 2024, the balance of restricted short-term investments was $2.2 million.

Deferred Income Taxes

The Company utilizes the liability method of accounting for income taxes, under which deferred taxes are determined based on the temporary differences between the financial statements and the tax basis of assets and liabilities using enacted tax rates. A valuation allowance is recorded when it is more likely than not that the deferred tax assets will not be realized.

Debt Issuance Costs

Debt issuance costs related to non-revolving debt are recognized as a reduction to the related debt balance in the accompanying condensed consolidated balance sheets and amortized to interest expense over the contractual term of the related debt using the effective interest method. Debt issuance costs associated with revolving debt are capitalized within other long-term assets on the condensed consolidated balance sheets and are amortized to interest expense over the term of the related revolving debt.

Convertible Debt

The Company accounts for its convertible debt instruments as a single unit of account, a liability, because the Company concluded that the conversion features do not require bifurcation as a derivative under Accounting Standards Codification, or ASC, 815-15,Derivatives and Hedging and the Company did not issue its convertible debt instruments at a substantial premium.

In accordance with Accounting Standards Update, or ASU,2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, the Company evaluates convertible debt instruments to determine if the conversion feature is freestanding or embedded. If the conversion feature does not require derivative treatment under ASC 815, the instrument is evaluated under ASC 470-20,“Debt with Conversion and Other Options” for consideration of any beneficial conversion features. If no beneficial conversion features exist that require separate recognition, convertible debt instruments are accounted for as a single liability measured at its amortized cost as long as no other features require separation and recognition as derivatives.

Capitalized Software Implementation Costs

The Company capitalizes certain software implementation costs incurred under a cloud computing arrangement that is a service contract. Costs incurred during the preliminary project phase or planning and research phase are expensed as

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incurred. Costs incurred during the application development stage related to the implementation of the hosting arrangement are capitalized and included within other assets on the accompanying condensed consolidated balance sheets. Capitalized implementation costs are amortized on a straight-line basis over the term of the associated hosting arrangement when ready for its intended use. Capitalized implementation costs were $4.9 million as of September 30, 2025 and are included in other long-term assets in the Company’s condensed consolidated balance sheet. As of December 31, 2024, the Company didnot have any capitalized implementation costs. For the three and nine months ended September 30, 2025 and 2024, the Company did not record any amortization expense for capitalized implementation costs.

Litigation, Commitments and Contingencies

Litigation, commitments and contingencies are accrued when management, after considering the facts and circumstances of each matter as then known, has determined it is probable a liability will be found to have been incurred and the amount of the loss can be reasonably estimated. When only a range of amounts is reasonably estimable and no amount within the range is more likely than another, the low end of the range is recorded. Legal fees are expensed as incurred. Due to the inherent uncertainties surrounding gain contingencies, the Company generally does not recognize potential gains until they are realized.

Recent Accounting Pronouncements

In December 2023, the Financial Accounting Standard Board, or FASB, issued ASU 2023-09,Income taxes (Topic 740): Improvements to Income Tax Disclosures, which requires entities, on an annual basis, to provide disclosure of specific categories in the rate reconciliation table, as well as disclosure of income taxes paid disaggregated by jurisdiction. The disclosure requirements will be applied prospectively, with retrospective application permitted. The standard is effective for the Company for fiscal years beginning after December 15, 2024, with early adoption permitted. The adoption will impact the Company’s disclosure, but is not expected to have a material impact on the Company’s results of operations or financial condition.

In November 2024, the FASB issued ASU 2024-03,Income Statement Reporting-Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40), Disaggregation of Income Statement Expenses. The standard update improves the disclosures about a public business entity’s expenses by requiring more detailed information about the types of expenses (including purchases of inventory, employee compensation, depreciation and amortization) included within income statement expense captions. The guidance will be effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The standard updates are to be applied prospectively with the option for retrospective application. The Company is currently evaluating the impact of disclosure requirements related to the new standard on its financial statements.

In September 2025, the FASB issued ASU 2025-06,Intangibles - Goodwill and Other-Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. The ASU amends the existing standard to remove all references to prescriptive and sequential software development project stages. Under this guidance, eligible software development costs will begin to be capitalized when management has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. In evaluating whether it is probable the project will be completed; management is required to consider whether there is significant uncertainty associated with the development activities of the software. This guidance is effective for all annual periods beginning after December 15, 2027, and for interim periods within those annual reporting periods, with early adoption permitted. The guidance may be applied on a prospective basis, a modified basis for in-process projects, or a retrospective basis. The Company is currently evaluating the impact of disclosure requirements related to the new standard on its financial statements.

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Note 3. Revenue Recognition

Product revenues, net

In accordance with ASC 606Revenue from Contracts with Customers, revenue is recognized at the time that the Company’s customers obtain control of the promised goods and we satisfy the Company’s performance obligations, which is generally at the time of product delivery to the Company’s customers. In some cases, the Company’s performance obligation is satisfied, and revenue is recognized at the time of shipment when stipulated by the terms of the sale agreements.

The consideration to which the Company expects to be entitled includes a stated list price, less various forms of variable consideration including provision for chargebacks and rebates, accrual for product returns, prompt pay discounts, distributor fees, patient co-pay assistance, and other related deductions. These deductions to product sales are referred to as gross-to-net deductions and are estimated and recorded in the period in which the related product sales occur. Payment terms offered to customers generally range from 30 to 75 days; however, payment terms differ by jurisdiction, by customer and, in some instances, by type of product. Revenues from product sales, net of gross-to-net deductions, are recorded only to the extent a significant reversal in the amount of cumulative revenue recognized is not probable of occurring when the uncertainty associated with gross-to-net deductions is subsequently resolved. Taxes assessed by governmental authorities and collected from customers are excluded from product sales. If the Company expects, at contract inception, that the period between the transfer of control and corresponding payment from the customer will be one year or less, the amount of consideration is not adjusted for the effects of a financing component. Shipping and handling activities are considered to be fulfillment activities rather than a separate performance obligation and are recorded within selling, distribution and marketing expenses in the accompanying condensed consolidated statements of operations.

*Provision for Chargebacks and Rebates:*The provision for chargebacks and rebates is a significant estimate used in the recognition of revenue. Wholesaler chargebacks relate to sales terms under which the Company agrees to reimburse wholesalers for differences between the gross sales prices at which the Company sells its products to wholesalers and the actual prices of such products that wholesalers resell under the Company’s various contractual arrangements with third parties such as hospitals, group purchasing organizations and pharmacy benefit managers in the United States. Rebates include primarily amounts paid to retailers, payers, and providers in the United States, including those paid to Medicare and state Medicaid programs, and are based on contractual arrangements or statutory requirements. The Company estimates chargebacks and rebates using the expected value method at the time of sale to customers based on inventory stocking levels, historical chargeback and rebate rates, and current contract pricing.

The provision for chargebacks and rebates is reflected as a component of product revenues, net. The following table is an analysis of the chargeback and rebate provision:

Changes in the chargeback provision from period to period are primarily dependent on the Company’s sales to its wholesalers, the level of inventory held by wholesalers, and the wholesalers’ customer mix. Changes in the rebate provision from period to period are primarily dependent on retailers’ and other indirect customers’ purchases. The approach that the Company uses to estimate chargebacks and rebates has been consistently applied for all periods presented. Variations in estimates have been historically small. The Company continually monitors the provision for chargebacks and rebates and makes adjustments when it believes that the actual chargebacks and rebates may differ from

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the estimates. Accounts receivable and/or accounts payable and accrued liabilities are reduced and/or increased by the chargebacks and rebate amounts depending on whether the Company has the right to offset with the customer.

The provision for chargebacks and rebates is included in the following balance sheet accounts:

*Accrual for Product Returns:*The Company offers certain customers the right to return qualified excess or expired inventory for full or partial credit. The Company’s product returns primarily consist of the returns of expired products from sales made in prior periods. Returned products cannot be resold. At the time product revenue is recognized, the Company records an accrual for product returns estimated using the expected value method. The accrual is based, in part, upon the historical relationship of product returns to sales and customer contract terms. The Company also assesses other factors that could affect product returns including market conditions, product obsolescence, and new competition.

Prompt Pay Discounts: The Company provides its customers with a percentage discount on their invoice if the customers pay within the agreed upon timeframe. The Company generally expects that its customers will earn such prompt pay discounts. The Company estimates the probability of customers paying promptly based on the percentage of discount outlined in the purchase agreement between the two parties, and deducts the full amount of these discounts from gross product sales and accounts receivable at the time revenue is recognized.

Distributor Fees: The Company engages with wholesalers to distribute its products to end customers. The Company pays the wholesalers a fee for services such as: inventory management, chargeback administration, and service level commitments. The Company estimates the amount of distribution services fees to be paid and adjusts the transaction price with the amount of such estimate at the time of sale to the customer. An accrued liability is recorded for unpaid distribution service fees.

Patient Co-Pay Assistance: Co-pay assistance represents financial assistance to qualified patients, assisting them with prescription drug co-payments required by insurance. The accrual for co-pay is based on an estimate of claims and the cost per claim that the Company expects to receive associated with inventory that exists in the distribution channel at period end.

Revenues derived from contract manufacturing services are recognized when third-party products are shipped to customers. The Company’s accounting policy is to review each agreement involving contract development and manufacturing services to determine if there are multiple revenue-generating activities that constitute more than one unit of account. Revenues are recognized for each unit of account based on revenue recognition criteria relevant to that unit.

Service revenues derived from research and development contracts are recognized over time based on progress toward satisfaction of the performance obligation. For each performance obligation satisfied over time, the Company assesses the proper method to be used for revenue recognition, either an input method to measure progress toward the satisfaction of services or an output method of determining the progress of completion of performance obligation. For the three and nine months ended September 30, 2025, revenues from research and development services at ANP were $1.9 million and $2.3 million, respectively. For the three and nine months ended September 30, 2024, revenues from research and development services were $0.1 million and $2.0 million, respectively.

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Note 4. Net Income per Share

Basic net income per share is calculated based upon the weighted-average number of shares outstanding during the period. Diluted net income per share gives effect to all potentially dilutive shares outstanding during the period, such as stock options, non-vested restricted stock units and shares issuable under the Company’s Employee Stock Purchase Plan, or ESPP, and potential shares of common stock issuable upon conversion of Convertible Notes of the Company, due March 2029, or the 2029 Convertible Notes.

For the three and nine months ended September 30, 2025, options to purchase 3,207,932 shares of stock, with a weighted-average exercise price of $35.01 per share, were excluded in the computation of diluted net income per share because their effect would be anti-dilutive. The 2029 Convertible Notes had no impact on the computation of diluted net income per share as the average stock price during the period was less than the conversion price.

For the three and nine months ended September 30, 2024, options to purchase 619,847 shares of stock, with a weighted-average exercise price of $46.63 per share, were excluded from the computation of diluted net income per share because their effect would be anti-dilutive. The 2029 Convertible Notes had no impact on the computation of diluted net income per share as the average stock price during the period was less than the conversion price.

The following table provides the calculation of basic and diluted net income per share for each of the periods presented:

Note 5. Segment Reporting

The Company’s business is the development, manufacture, and marketing of pharmaceutical products (see Note 1). The Company’s Chief Executive Officer is the Chief Operating Decision Maker, or CODM.

During the three and nine months ended September 30, 2025, the Company hadone reportable segment. The measure of segment assets is reported on the condensed consolidated balance sheets as total assets.

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Selected segment financial information is presented below. As a result of the change to one reportable segment in the fourth quarter of 2024, the Company has recast the segment information for the prior periods presented:

Net revenues by product are presented below:

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Net revenues and carrying values of long-lived assets, which includes property, plant and equipment, as well as finance and operating lease right-of-use assets, by geographic region, based on where the Company conducts its operations are as follows:

Note 6. Customer and Supplier Concentration

Customer Concentrations

The following table provides accounts receivable and net revenue information for the Company’s three major customers:

Supplier Concentrations

The Company depends on suppliers for raw materials, APIs, and other components that are subject to stringent FDA requirements. Some of these materials may only be available from one or a limited number of sources. Establishing additional or replacement suppliers for these materials may take a substantial period of time, as suppliers must be approved by the FDA. Furthermore, a significant portion of raw materials may only be available from foreign sources. If the Company is unable to secure, on a timely basis, sufficient quantities of the materials it depends on to manufacture and market its products, it could have a materially adverse effect on the Company’s business, financial condition, and results of operations.

Note 7. Fair Value Measurements

GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants in the principal or most advantageous market for the asset or liability at the measurement date (an exit price). These standards also establish a hierarchy that prioritizes observable and unobservable inputs used in measuring fair value of an asset or liability, as described below:

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As of September 30, 2025 and December 31, 2024, cash equivalents include money market accounts and corporate and municipal bonds with original maturities of less than three months. Investments consist of certificates of deposit as well as investment-grade corporate, agency and municipal bonds with original maturity dates between three and nineteen months. The certificates of deposit are carried at amortized cost in the Company’s condensed consolidated balance sheets, which approximates their fair value determined based on Level 2 inputs. The corporate, agency and municipal bonds are classified as held-to-maturity and are carried at amortized cost net of allowance for credit losses. The fair value of such bonds is disclosed in Note 8 and was determined based on Level 2 inputs. The restrictions on restricted cash and investments have an immaterial effect on the fair value of these financial assets.

The fair values of the Company’s financial assets and liabilities measured on a recurring basis as of September 30, 2025 and December 31, 2024, are as follows:

The Company does not hold any Level 3 instruments that are measured at fair value on a recurring basis.

Nonfinancial assets and liabilities are not measured at fair value on a recurring basis but are subject to fair value adjustments in certain circumstances. These items primarily include investments in unconsolidated affiliates, long-lived assets, goodwill, and intangible assets for which the fair value is determined as part of an impairment test. As of September 30, 2025 and December 31, 2024, there were no significant adjustments to fair value for nonfinancial assets or liabilities.

The Company’s deferred compensation plan assets are valued using the cash surrender value of the life insurance policies and are not included in the table above.

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Note** 8. Investments**

The following is a summary of the Company’s investments that are classified as held-to-maturity:

At each reporting period, the Company evaluates securities for impairment when the fair value of the investment is less than its amortized cost. The Company evaluated the underlying credit quality and credit ratings of the issuers, identifying neither a significant deterioration since purchase nor any other factors that would indicate a material credit loss.

The Company measures expected credit losses on held-to-maturity investments on a collective basis. All the Company’s held-to-maturity investments were considered to be one pool. The estimate for credit losses considers historical loss information that is adjusted for current conditions and reasonable and supportable forecasts. Expected credit losses on held-to-maturity investments were not material to the condensed consolidated financial statements.

Note** 9. Goodwill and Intangible Assets**

The table below shows the weighted-average life, original cost, accumulated amortization, and net book value by major intangible asset classification:

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• Intangible assets with indefinite lives have an indeterminable average life.

Goodwill

The changes in the carrying amounts of goodwill are as follows:

Note 10. Inventories

Inventories consist of the following:

Charges of $1.3 million and $4.2 million were included in the cost of revenues in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2025, respectively, to adjust the Company’s inventory and related firm purchase commitments to its net realizable value. For the three and nine months ended September 30, 2024, charges of $0.9 million and $10.1 million were included in the cost of revenues, respectively, to adjust the Company’s inventory and related firm purchase commitments to its net realizable value.

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Note 11. Property, Plant, and Equipment

Property, plant, and equipment consist of the following:

Note 12. Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities consisted of the following:

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Note** 13. Debt**

Debt consists of the following:

Credit Agreement

2029 Convertible Notes

In September 2023, the Company issued the 2029 Convertible Notes, in the aggregate principal amount of $345.0 million in a private offering pursuant to Section 4(a)(2) and Rule 144A under the Securities Act of 1933, as amended. The Company used portions of the net proceeds from the 2029 Convertible Notes to (i) repay approximately $200.0 million of the Company’s borrowings under the Wells Fargo Term Loan and (ii) repurchase $50.0 million of the Company’s common stock.

In connection with the issuance of the 2029 Convertible Notes, the Company incurred approximately $10.8 million of debt issuance costs, which primarily consisted of underwriting, legal and other professional fees. Unamortized debt issuance costs related to the 2029 Convertible Notes were $6.8 million and $8.3 million as of September 30, 2025 and December 31, 2024, respectively. The fair value of the 2029 Convertible Notes was approximately $314.0 million as of September 30, 2025 based on Level 2 inputs.

For the three and nine months ended September 30, 2025, the total interest expense related to the 2029 Convertible Notes was $2.2 million and $6.7 million, with coupon interest expense of $1.7 million and $5.2 million, and the amortization of debt issuance cost of $0.5 million and $1.5 million, respectively. For the three and nine months ended September 30, 2024, the total interest expense related to the 2029 Convertible Notes was $2.5 million and $6.7 million, with coupon interest expense of $2.0 million and $5.2 million, and the amortization of debt issuance cost of $0.5 million and $1.5 million, respectively.

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The 2029 Convertible Notes are general senior, unsecured obligations and bear an interest rate of 2.0% per year. The 2029 Convertible Notes were issued pursuant to an indenture, dated September 15, 2023, or the Indenture, between the Company and U.S. Bank Trust Company, National Association, as trustee.

The 2029 Convertible Notes will rank senior in right of payment to all of the Company’s indebtedness that is expressly subordinated in right of payment to the 2029 Convertible Notes; equal in right of payment to all of the Company’s unsecured indebtedness that is not so subordinated; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness, including any amount outstanding under the Company’s credit facilities; and structurally junior to all indebtedness and other liabilities of the Company’s current or future subsidiaries, including trade payables.

Interest is payable semi-annually in arrears on March 15 and September 15 of each year. The 2029 Convertible Notes may bear additional interest under specified circumstances relating to the Company’s failure to comply with its reporting obligations under the Indenture or if the 2029 Convertible Notes are not freely tradeable as required by the Indenture.

The 2029 Convertible Notes will mature on March 15, 2029, unless earlier converted, repurchased or redeemed.

Conversions of the 2029 Convertible Notes will be settled in cash up to the aggregate principal amount of the 2029 Convertible Notes to be converted, and cash, shares of common stock or a combination of cash and shares of common stock, at the Company’s election, with respect to the remainder, if any, of the Company’s conversion obligation in excess of the aggregate principal amount.

Holders may convert their 2029 Convertible Notes at their option prior to the close of business on the business day immediately preceding December 15, 2028, in multiples of $1,000 principal amount, only under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on December 31, 2023 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the 2029 Convertible Notes on each applicable trading day, (ii) during thefive business day period after anyfive consecutive trading day period in which the trading price, as defined in the Indenture, per $1,000 principal amount of the 2029 Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day, (iii) if the Company calls the 2029 Convertible Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date, and (iv) upon the occurrence of specified corporate events defined in the Indenture.

On or after December 15, 2028, until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their 2029 Convertible Notes, in multiples of $1,000 principal amount, at the option of the holder regardless of the foregoing circumstances.

The Company may redeem the 2029 Convertible Notes, at its option, in whole or in part (subject to certain limitations), on or after September 20, 2026 and prior to the 41 st scheduled trading day preceding the maturity date, if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on and including the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2029 Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.

The initial conversion rate is 15.8821 shares of the Company’s common stock per $1,000 principal amount of the 2029 Convertible Notes, which represents an initial conversion price of approximately $62.96 per share of common stock. The initial conversion price of $62.96 represents a premium of approximately 35.0% over the last reported sale price of the Company’s common stock on Nasdaq Global Select Market on September 12, 2023. The conversion rate is subject to

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adjustment under certain circumstances in accordance with the terms of the Indenture.

If a fundamental change, as defined in the Indenture, occurs at any time prior to the maturity date, then, subject to certain conditions, holders of the 2029 Convertible Notes may require the Company to repurchase for cash all or any portion of their 2029 Convertible Notes at a repurchase price equal to 100% of the principal amount of the 2029 Convertible Notes to be repurchased, plus any accrued and unpaid interest. In addition, following certain specified corporate events or if the Company issues a notice of redemption, the Company will, under certain circumstances, increase the conversion rate for holders who convert their 2029 Convertible Notes in connection with such corporate event or during a redemption period.

Syndicated Line of Credit Facility with ICBC Bank – Due November 2033

In January 2024, the Company entered into a credit agreement with Industrial and Commercial Bank of China Limited, or ICBC Bank, acting as a lender and as agent for other lenders. The credit agreement allows the Company to borrow up to $40.0 million secured by equipment and buildings at ANP. The interest rate and other terms will be determined at the time of the borrowing, depending on the type of loan requested. The credit agreement expires in November 2033.

The loan bears interest at the prime rate as published by The People’s Bank of China minus 0.2%. Interest payments are due quarterly and repayment of the principal amount is biannual and begins in May 2026. As of September 30, 2025, the Company had $24.4 million of principal outstanding under this loan, which is recorded net of loan issuance costs of $1.3 million.

Interest Rate Swap Contract

As of September 30, 2025, the fair value of the loans listed above approximated their carrying amount based on Level 2 inputs, with the exception of the 2029 Convertible Notes. For the Wells Fargo Term Loan, the Company has entered into a fixed interest rate swap contract to exchange the variable interest rates for fixed interest rates. The interest rate swap contract is recorded at fair value in the other long-term liabilities line in the condensed consolidated balance sheets. Changes in the fair values of interest rate swaps resulted in animmaterial amount for the three months ended September 30, 2025. For the nine months ended September 30, 2025, the change in the fair values of interest rate swaps was a loss of $4.6 million. Changes in the fair values of interest rate swaps were a $7.4 million loss and a $1.6 million loss for the three and nine months ended September 30, 2024, respectively.

Covenants

At September 30, 2025 and December 31, 2024, the Company was in compliance with all of its debt covenants.

Note 14. Income Taxes

The following table sets forth the Company’s income tax provision for the periods indicated:

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Valuation Allowance

In assessing the need for a valuation allowance, management considers whether it is more likely than not that some portion or all of the deferred income tax assets will be realized. Ultimately, realization depends on the existence of future taxable income. Management considers sources of taxable income such as income in prior carryback periods, future reversal of existing deferred taxable temporary differences, tax-planning strategies, and projected future taxable income.

The Company continues to record a full valuation allowance on the net deferred income tax assets of its French subsidiary, AFP, and its U.K. subsidiaries, AUK and IMS UK, and will continue to do so until the subsidiaries generate sufficient taxable income to realize their respective deferred income tax assets.

The Company also records a valuation allowance on net deferred income tax assets in states where it files separately and will continue to do so until sufficient taxable income is generated to realize these state deferred income tax assets.

Tax Law Updates

On July 4, 2025, the One Big Beautiful Bill Act, or OBBBA, was enacted into law. The OBBBA includes significant provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act, modifications to the international tax framework and the restoration of favorable tax treatment for certain business provisions. As of September 30, 2025, the Company does not expect the provisions of the OBBBA will have a material impact on income tax expense, but the Company does expect certain provisions will change the timing of cash tax payments in the current year and future periods.

Note 15. Stockholders' Equity

Share Buyback Program

Pursuant to the Company’s existing share buyback program, the Company purchased 172,920 and 2,108,616 shares of its common stock, during the three and nine months ended September 30, 2025, for total consideration of $4.9 million and $54.9 million, respectively. The Company purchased 797,038 shares and 1,004,326 shares of its common stock during the three and nine months ended September 30, 2024, for total consideration of $35.0 million and $43.5 million, respectively.

In August 2025, the Company’s Board of Directors authorized a $50.0 million increase to the Company’s share buyback program, which is expected to continue for an indefinite period of time. Since the inception of the program, the Company’s Board of Directors have authorized a total of $435.0 million in the share buyback program. The primary goal of the program is to offset dilution created by the Company’s equity compensation programs.

Purchases are made through open market and private block transactions pursuant to Rule 10b5-1 plans, privately negotiated transactions or other means as determined by the Company’s management and in accordance with the requirements of the SEC and applicable laws. The timing and actual number of treasury share purchases will depend on a variety of factors including price, corporate and regulatory requirements, and other conditions. These treasury share purchases are accounted for under the cost method and are included as a component of treasury stock in the Company’s condensed consolidated balance sheets.

Amended and Restated 2015 Equity Incentive Plan

In February 2024, the Board of Directors approved the Company’s amended and restated 2015 Equity Incentive Plan, or the Amended 2015 Plan, which was subsequently approved by the Company’s stockholders, and accordingly, adopted by the Company in June 2024. The Amended 2015 Plan, among other things, extended the term of the 2015 Equity Incentive Plan, or the Original 2015 Plan, increased the number of shares available for issuance under the Original 2015 Plan, and removed the evergreen provision. The term of the Amended 2015 Plan will be extended indefinitely, however, the Company’s ability to grant incentive stock options thereunder will continue through February 2034.

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As of September 30, 2025, the Company reserved an aggregate of 6,614,915 shares of common stock for future issuance under the Amended 2015 Plan.

2014 Employee Stock Purchase Plan

As of September 30, 2025, the Company has issued 1,378,506 shares of common stock under the ESPP and 621,494 shares of its common stock remain available for issuance under the ESPP.

In May 2025, the Company issued 89,054 shares at a purchase price of $21.85 per share under the ESPP. For the three and nine months ended September 30, 2025, the Company recorded ESPP expense of $0.2 million and $0.9 million, respectively. For the three and nine months ended September 30, 2024, the Company recorded ESPP expense of $0.2 million and $0.9 million, respectively.

Share-Based Award Activity and Balances

The Company accounts for share-based compensation payments in accordance with ASC 718, which requires measurement and recognition of compensation expense at fair value for all share-based payment awards made to employees and directors. Under these standards, the fair value of option awards and the option components of the ESPP awards are estimated at the grant date using the Black-Scholes option-pricing model. The fair value of RSUs is estimated at the grant date using the Company’s common share price. The Company records share-based compensation expense net of expected forfeitures. Compensation cost for all share-based payments granted with service-based graded vesting schedules is recognized using the straight-line method over the requisite service period.

The weighted-averages for key assumptions used in determining the fair value of options granted are as follows:

A summary of option activity under all plans for the nine months ended September 30, 2025, is presented below:

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For the three and nine months ended September 30, 2025, the Company recorded expense of $3.0 million and $10.2 million, respectively, related to stock options granted under all plans. For the three and nine months ended September 30, 2024, the Company recorded expense of $2.7 million and $9.0 million, respectively, related to stock options granted under all plans.

Information relating to option grants and exercises is as follows:

A summary of the status of the Company’s non-vested options as of September 30, 2025, and changes during the nine months ended September 30, 2025, are presented below:

As of September 30, 2025, there was $23.9 million of total unrecognized compensation cost, net of forfeitures, related to non-vested stock option based compensation arrangements granted under all plans. The cost is expected to be recognized over a weighted-average period of 2.6 years and will be adjusted for future changes in estimated forfeitures.

Restricted Stock Units

The Company grants restricted stock units, or RSUs, to certain employees and members of the Board of Directors with a vesting period of up tofour years. The grantee receivesone share of common stock at a specified future date for each RSU awarded. The RSUs may not be sold or otherwise transferred until vested. The RSUs do not have any voting or dividend rights prior to the issuance of the underlying common stock. The share-based expense associated with these grants was based on the Company’s common stock fair value at the time of grant and is amortized over the requisite service period, which generally is the vesting period using the straight-line method. For the three and nine months ended September 30, 2025, the Company recorded total expenses of $3.0 million and $10.0 million, respectively, related to RSU awards granted under all plans. For the three and nine months ended September 30, 2024, the Company recorded expenses of $2.7 million and $8.8 million, respectively, related to RSU awards granted under all plans.

As of September 30, 2025, there was$25.4 million of total unrecognized compensation cost, net of forfeitures, related to non-vested RSU-based compensation arrangements granted under all plans. The cost is expected to be recognized over a weighted-average period of 2.6 years and will be adjusted for future changes in estimated forfeitures.

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Information relating to RSU grants and deliveries is as follows:

Share-based Compensation Expense

The Company recorded share-based compensation expense, which is included in the Company’s condensed consolidated statement of operations, as follows:

Note 16. Employee Benefits

401(k) Plan

The Company has a defined contribution 401(k) plan, or the Plan, whereby eligible employees voluntarily contribute up to a defined percentage of their annual compensation. The Company matches contributions at a rate of 50% on the first 6% of employee contributions, and pays the administrative costs of the Plan. Total employer contributions for the three and nine months ended September 30, 2025 were approximately $0.6 million and $2.0 million, respectively, compared to the prior year expense of $0.6 million and $2.0 million for the three and nine months ended September 30, 2024, respectively.

Defined Benefit Pension Plan

The Company’s subsidiary, AFP, has an obligation associated with a defined-benefit plan for its eligible employees. This plan provides benefits to the employees from the date of retirement and is based on the employee’s length of time employed by the Company. The calculation is based on a statistical calculation combining a number of factors that include the employee’s age, length of service, and AFP employee turnover rate.

The liability under the plan is based on a discount rate of 3.40% as of September 30, 2025 and December 31, 2024. The liability is included in other long-term liabilities in the accompanying condensed consolidated balance sheets. The plan is currently unfunded, and the benefit obligation under the plan was $2.9 million and $2.6 million at September 30, 2025 and December 31, 2024, respectively. The Company recorded an immaterial amount of expense under the plan for each of the three and nine months ended September 30, 2025 and 2024.

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Non-qualified Deferred Compensation Plan

In December 2019, the Company established a non-qualified deferred compensation plan. The plan allows certain eligible participants to defer a portion of their cash compensation and provides a matching contribution at the discretion of the Company. The plan obligations are payable upon retirement, termination of employment and/or certain other times in a lump-sum distribution or in installments, as elected by the participant in accordance with the plan. Participants can allocate their deferred compensation amongst various investment options with earnings accruing to the participant. The Company has established a Rabbi Trust to fund the plan obligations and to hold the plan assets. Eligible participants began contributing to the plan in January 2020. The plan assets were valued at approximately $13.3 million and $10.3 million as of September 30, 2025 and December 31, 2024, respectively. The plan liabilities were valued at approximately $13.8 million and $10.7 million as of September 30, 2025, and December 31, 2024, respectively. The plan assets and liabilities are included in other long-term assets and other long-term liabilities, respectively, on the Company’s condensed consolidated balance sheets.

Note 17. Commitments and Contingencies

New Real Estate Lease Agreement

In July 2025, the Company entered into an agreement to lease approximately 225,167 square feet of building space in Rancho Cucamonga, California. The non-cancelable lease term is approximately 10 years commencing on January 1, 2026 with a renewal option to extend the lease fortwo additional five-year periods. The monthly lease payments are $0.3 million subject to an annual increase of 3.25%. For the three and nine months ended September 30, 2025, the Company did not recognized any lease expense given that the lease has not yet commenced.

Licensing Agreement with Nanjing Anji Biotechnology Co., Ltd.

In August 2025, the Company and Nanjing Anji Biotechnology Co., Ltd., or Anji, entered into a License Agreement, or License Agreement, pursuant to which Anji has granted the Company an exclusive license to certain intellectual property to develop, make, use and commercialize products incorporating or comprising certain compounds, including three identified products, or Licensed Products, in the United States and Canada, or the Territory. Anji has also been granted a non-exclusive license under certain intellectual property controlled by the Company to develop, make, use and commercialize Licensed Products outside the Territory. During the second quarter of 2025, the Company made an earnest money payment of $0.7 million, which was recorded as research and development expense in the Company’s condensed consolidated statement of operations. Upon signing the License Agreement with Anji, the Company made an upfront payment of $5.3 million. For the three and nine months ended September 30, 2025, the Company paid $5.3 million and $6.0 million, respectively, relating to the agreement, which was recorded as a research and development expense in the Company’s condensed consolidated statement of operations.

The Company is also required to make payments to Anji of up to $42.0 million in development-based milestone payments and up to $225.0 million in sales-based milestone payments, subject to the achievement of the applicable development and sales milestone events respectively, and royalty payments of 5% on net sales, not to exceed a maximum annual amount of $22.5 million each calendar year for each Licensed Product and a maximum accumulated amount of $60.0 million for each Licensed Products. The Company is also required to pay Anji a certain percentage of sublicense income received from the sublicense transactions. The term of this License Agreement will expire, on a Licensed Product-by-Licensed Product and region-by-region basis, on the tenth anniversary of the first commercial sale of such Licensed Product in the applicable region in the Territory, with the Company having the right to extend the License Agreement until the earlier of ten additional years or the expiration, lapse, or invalidation of the last remaining valid claim of the patents licensed by Anji to the Company that covers the Licensed Products in the Territory.

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Note 18. Related Party Transactions

Hanxin Pharmaceutical Technology, Co., Ltd.

The Company has an 11.5% ownership in Hanxin that is accounted for as an equity method investment. The Company maintains a seat on Hanxin’s board of directors, and Henry Zhang, the son of Dr. Jack Zhang, is an equity holder, the general manager, and the chairman of the board of directors of Hanxin. Additionally, Dr. Mary Luo and Dr. Jack Zhang, have an ownership interest in Hanxin through an affiliated entity. As a result, Hanxin is a related party.

Contract Manufacturing Agreements with Hanxin

The Company has various contract manufacturing agreements with Hanxin and its subsidiaries, whereby Hanxin will develop several active pharmaceutical ingredients and finished products for the Chinese market and will engage the Company to manufacture the products on a cost-plus basis.

During the three months ended September 30, 2025, the Company recognized animmaterial amount of revenue from manufacturing services provided to Hanxin. During the nine months ended September 30, 2025, the Company recognized $0.3 million of revenue from manufacturing services provided to Hanxin. During the three and nine months ended September 30, 2024, the Company recognized $0.1 million and $0.5 million, respectively, of revenue from manufacturing services provided to Hanxin. As of September 30, 2025 and December 31, 2024, the Company had receivables of approximately $0.5 million and $0.2 million from Hanxin under these agreements, respectively.

Contract Research Agreement with Hanxin

The Company has entered into various contract research agreements with Hanxin, a related party, whereby Hanxin will develop Recombinant Human Insulin Research Cell Banks and Recombinant Peptide Research Cell Banks, or RCBs, for the Company and license the RCBs to the Company subject to a fully paid, exclusive, perpetual, transferable, sub-licensable worldwide license. Hanxin will also perform scale-up manufacturing process development using the RCBs for the Company.

During the three and nine months ended September 30, 2025, the Company paid an immaterial amount under the agreements. During the three months ended September 30, 2024, the Company didnot have any payments under the amended agreement and during the nine months ended September 30, 2024, the Company paid $0.2 million under the amended agreement. As of September 30, 2025 and December 31, 2024, the Company had an immaterial amount payable to Hanxin under this agreement.

Supply Agreement with Letop

In November 2022, the Company, entered into a supply agreement with Nanjing Letop Biotechnology Co., Ltd., or Letop, which is considered a related-party due to an ownership stake of Henry Zhang. Under the terms of the supply agreement Letop will manufacture and deliver chemical intermediates to the Company on a cost-plus basis. The agreement is effective for three years and the total cost of the agreement shall not exceed $1.5 million, with payments adjusted based on the then current exchange rates.

During the three months ended September 30, 2025, the Company didnot make any payments under this agreement. During the nine months ended September 30, 2025, the Company paid animmaterial amount under this agreement. During the three and nine months ended September 30, 2024, the Company paid an immaterial amount under this agreement. As of September 30, 2025 and December 31, 2024, the Company did not have any amounts payable to Letop.

Primatene MIST®* Distribution Agreement with Hong Kong Genreach Limited*

In August 2024, the Company entered into a distribution agreement with Hong Kong Genreach Limited, or Genreach, a wholly owned subsidiary of Hanxin, a related party. Per the terms of the agreement, the Company has appointed

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Genreach as the exclusive distributor to market and sell Primatene MIST® in Mainland China, Taiwan, Hong Kong, and Macau in the Greater China region. Genreach will be responsible for obtaining any and all regulatory approvals in the region for Primatene MIST®.

The term of the agreement is for ten years, with both parties having termination rights without cause after the completion of the second contract year.

During the three and nine months ended September 30, 2025, the Company did not recognize any revenue from the distribution agreement with Genreach. As of September 30, 2025 and December 31, 2024, the Company did not have any receivables from Genreach.

BAQSIMI®* Distribution Agreement with Nanjing Chengong Pharmaceutical Co., Limited.*

In October 2025, the Company entered into a distribution agreement with Nanjing Chengong Pharmaceutical Co., Limited, or Chengong, a wholly-owned subsidiary of Hanxin, a related party. Per the terms of the agreement, the Company will collaborate with Chengong to expand distribution of BAQSIMI®, in Mainland China, Taiwan, Hong Kong, and Macau in the Greater China region, and appoint Chengong as the exclusive distributor to market and sell BAQSIMI® in the Greater China Region. Chengong is responsible for obtaining any and all regulatory approvals in the Region, and performing the required post marketing clinical trials for BAQSIMI®.

The term of the agreement is forten years, with both parties having termination rights without cause after the completion of the fourth contract year.

Note 19. Litigation

Employee Litigations

On April 15, 2024, a former employee initiated an employment litigation against Amphastar and IMS by filing a complaint, as amended, having individual and class action claims for alleged violations of the California Labor Code pertaining to California’s Private Attorneys General Act, or PAGA, wage and hour, and other state laws. This complaint was filed in the Superior Court of California for the County of Los Angeles. In the complaint, the plaintiff is seeking damages and related remedies under California Law, as well as various penalty payments under the California Labor Code. In November 2024, the court ordered the plaintiff to dismiss the individual and class claims, with only the PAGA claim remaining. The Company intends to vigorously defend itself against the complaint.

On June 20, 2024, a former employee initiated an employment litigation against Amphastar, IMS and Roth Staffing Companies L.P. by filing a complaint having individual and class action claims for alleged violations of the California Labor Code pertaining to wage and hour, and other state laws. This complaint was filed in the Superior Court of California for the County of Los Angeles. In the complaint, the plaintiff is seeking damages and related remedies under California Law, as well as various penalty payments under the California Labor Code. The Company intends to vigorously defend itself against the complaint.

Other Litigation

On August 23, 2023, the Company was subject to a personal injury lawsuit. A jury trial was held in the Superior Court of California, for the County of San Bernardino from September 2025 to October 2025. On October 22, 2025, the jury returned a verdict awarding the plaintiff $34.1 million, of which $11.0 million is covered by the Company’s insurance policies, and is recorded within prepaid expenses and other current assets with a corresponding accrued liability on the condensed consolidated balance sheet as of September 30, 2025. The remaining $23.1 million was accrued during the third quarter of 2025 within general and administrative expenses in the Company’s condensed consolidated statement of operations. As of December 31, 2024, the Company recorded $6.0 million in prepaids and other current assets with a corresponding accrued liability on the condensed consolidated balance sheet. The Company is currently exploring all

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post-verdict options, including an opportunity to appeal the decision of the court, and vigorously defend itself in this matter.

The Company is also subject to various other claims, arbitrations, investigations, and lawsuits from time to time arising in the ordinary course of business. In addition, third parties may, from time to time, assert claims against the Company in the forms of letters and other communications.

The Company records a provision for contingent losses when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. In the opinion of management, the ultimate resolution of any such matters is not expected to have a material adverse effect on its financial position, results of operations, or cash flows; however, the results of litigation and claims are inherently unpredictable and the Company’s view of these matters may change in the future. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources, and other factors.

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