ASSEMBLY BIOSCIENCES, INC. 10-K

Item 9A. Controls and Procedures Evaluation of Disclosure Controls and Procedures We maintain a system of disclosure controls and procedures, as defined in Rule 13a-15(e) promulgated under the Securities Exchange Act of 1934, as amended (the Exchange Act), that is designed to provide reasonable assurance that information, which is required to be disclosed in our reports filed pursuant to the Exchange Act, is accumulated and communicated to management in a timely manner. At the end of fiscal year ending December 31, 2025, we carried out an evaluation, under the supervision, and with the participation of, our management, including our Chief Executive Officer and President, who serves as our principal executive officer, and our VP, Finance, who serves as our principal financial officer, of the effectiveness of the design and operation of our disclosure controls and procedures pursuant to Exchange Act Rule 13a-15(b). Based upon that evaluation, our Chief Executive Officer and President and our VP, Finance concluded that our disclosure controls and procedures for the fiscal year ending as of December 31, 2025 were effective at reasonable assurance levels. Management’s Annual 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 Exchange Act Rule 13a-15(f). Our internal control over financial reporting is designed to provide reasonable assurance to our management and board of directors regarding the preparation and fair presentation of published financial statements. A control system, no matter how well designed and operated, can only provide reasonable, not absolute, assurance that the objectives of the control system are met. Because of these inherent limitations, management does not expect that our internal controls over financial reporting will prevent all error and all fraud. Under the supervision and with the participation of our management, including our Chief Executive Officer and President, who serves as our principal executive officer, and our VP, Finance, who serves as our principal financial officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting based on the framework in Internal Control-Integrated Framework issued in 2013 by the Committee of Sponsoring Organizations of the Treadway Commission. Based on our evaluation under the framework in Internal Control-Integrated Framework, our management concluded that our internal control over financial reporting was effective as of December 31, 2025. Changes in Internal Control over Financial Reporting There were no changes in our internal control over financial reporting in the fourth quarter of 2025 that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. Item 9B. Other Information No t applicable. Ite m 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections Not applicable. 60 PART III Item 10. Directors, Executive Of ficers and Corporate Governance Except as set forth below, the information required by this item will be contained in our definitive proxy statement to be filed with the SEC in connection with the Annual Meeting of Stockholders (Proxy Statement) within 120 days after the conclusion of our fiscal year ended December 31, 2025 and is incorporated in this Annual Report on Form 10-K by reference. Code of Ethics Our Board has adopted a Code of Ethics for our principal executive officer and all senior financial officers and a Code of Conduct applicable to all of our employees and our directors. Both Codes are available under the “Investors—Corporate Governance” section of our website at www.assemblybio.com. If we make any substantive amendments to, or grant any waivers from, the Code of Ethics for our principal executive officer, principal financial officer, principal accounting officer, controller or persons performing similar functions, or any officer or director, we will disclose the nature of such amendment or waiver on our website or in a Current Report on Form 8-K. Item 11. Execut ive Compensation The information required by this item will be contained in the Proxy Statement and is incorporated into this Annual Report on Form 10-K by reference. Item 12. Security Ownership of Certain Beneficial Ow ners and Management and Related Stockholder Matters Except for the table regarding equity compensation plans, the information required by this item will be contained in the Proxy Statement and is incorporated into this Annual Report on Form 10-K by reference. Securities Authorized for Issuance Under Equity Compensation Plans The following table sets forth the indicated information as of December 31, 2025 with respect to our equity compensation plans. Plan Category Number of securities to be issued upon exercise of outstanding options, warrants and rights (a) Weighted average exercise price of outstanding options, warrants and rights (1) (b) Number of securities remaining available for future issuance under equity compensation plans (excluding securities reflected in column (a)) (c) Equity compensation plans approved by security holders 1,368,993 (2) $ 23.71 479,093 (3) Equity compensation plans not approved by security holders 10,679,161 (4) $ 20.66 14,594 (5) Total 12,048,154 493,687 (1) The weighted average exercise price is calculated solely based on the exercise prices of the outstanding stock options and warrants and does not reflect the shares that will be issued upon the vesting of outstanding awards of restricted stock units (RSUs) or performance stock units (PSUs), which have no exercise price. 61 (2) This number includes the following: 15,196 shares subject to stock options granted under the 2010 Equity Incentive Plan (2010 Plan); 205,462 shares subject to outstanding awards granted under the Assembly Biosciences, Inc. Amended and Restated 2014 Stock Incentive Plan (2014 Plan), of which 204,692 were subject to outstanding stock options and 770 were subject to outstanding RSUs; and 1,148,335 shares subject to outstanding awards granted under the Assembly Biosciences, Inc. Amended and Restated 2018 Stock Incentive Plan, as amended (2018 Plan), of which 822,690 were subject to outstanding stock options, 84,813 were subject to outstanding RSUs and 240,832 were subject to outstanding PSUs. This number excludes purchase rights currently accruing under the Assembly Biosciences, Inc. Second Amended and Restated 2018 Employee Stock Purchase Plan (ESPP). (3) This number includes: no shares under the 2010 Plan, which has been frozen; 9,606 shares available for issuance under the 2014 Plan; 383,390 shares available for issuance under the 2018 Plan; and 86,097 shares reserved for issuance under the ESPP. (4) This number includes 50,452 shares subject to stock options granted under the 2017 Inducement Award Plan (2017 Inducement Plan); 41,666 shares subject to stock options granted under the 2019 Inducement Award Plan (2019 Inducement Plan); 58,746 shares subject to stock options granted under the 2020 Inducement Award Plan (2020 Inducement Plan); and 10,528,297 warrants granted in offerings in June 2024 and August 2025. (5) This number includes: 14,589 shares available for issuance under the 2017 Inducement Plan, no shares under the 2019 Inducement Plan and 5 shares available for issuance under the 2020 Inducement Plan. Our stockholder-approved equity compensation plans consist of the 2018 Plan, the 2014 Plan, the 2010 Plan and the ESPP. Effective on June 2, 2016, the 2010 Plan was frozen, and no further grants will be made under the 2010 Plan. Shares that are forfeited under the 2010 Plan on or after June 2, 2016 will become available for issuance under the 2014 Plan. An “Award” under the 2018 Plan, 2014 Plan or 2010 Plan is any right to receive our common stock consisting of non-statutory stock options, incentive stock options, stock appreciation rights, RSUs, PSUs, or any other stock award. In May 2018, our stockholders approved the ESPP, which was amended and restated in May 2021, May 2024 and June 2025. The ESPP provides for the purchase by employees of up to an aggregate of 225,000 shares of the Company’s common stock at the end of predetermined offering periods at 85% of the lower of the fair market value at the beginning or end of each offering period. Eligible employees may participate in the ESPP at a minimum of 1% and up to a maximum of 15% of such employee’s compensation for each pay period, subject to annual statutory limits. Our outstanding equity compensation arrangements that have not been approved by our stockholders consist of the 2017 Inducement Plan, the 2019 Inducement Plan, the 2020 Inducement Plan and warrants granted in a registered direct offering and a private placement in June 2024. In April 2017, our board of directors adopted the 2017 Inducement Plan and reserved 66,666 shares of our common stock for issuance under the 2017 Inducement Plan. In August 2019, our board of directors adopted the 2019 Inducement Plan and reserved 41,666 shares of our common stock for issuance under the 2019 Inducement Plan. In March 2020, our board of directors adopted the 2020 Inducement Plan and reserved 66,666 shares of our common stock for issuance under the 2020 Inducement Plan. The only persons eligible to receive grants of awards under the 2017 Inducement Plan, the 2019 Inducement Plan or the 2020 Inducement Plan are individuals who satisfy the standards for inducement grants under Nasdaq Marketplace Rule 5635(c)(4) and the related guidance under Nasdaq IM 5635-1-that is, generally, a person not previously an employee or director of ours, or following a bona fide period of non-employment, as an inducement material to the individual's entering into employment with us. An “Award” is any right to receive our common stock pursuant to the Inducement Plan, consisting of non-statutory stock options, stock appreciation rights, restricted stock awards, RSUs, PSUs, or any other stock award. Item 13. Certain Relationships and Related P arty Transactions, and Director Independence The information required by this item will be contained in the Proxy Statement and is incorporated into this Annual Report on Form 10-K by reference. 62 Item 14. Principal Acco untant Fees and Services The information required by this item will be contained in the Proxy Statement and is incorporated into this Annual Report on Form 10-K by reference. 63 Item 15. Exhibits, Finan cial Statement Schedules (a) Exhibits. The following exhibits are filed as part of this Annual Report on Form 10-K: Exhibit Number Description of Document Registrant’s Form Dated Exhibit No. Filed Herewith 3.1 Sixth Amended and Restated Certificate of Incorporation dated May 25, 2022. 10-K 03/28/2024 3.1 3.2 Certificate of Amendment to Sixth Amended and Restated Certificate of Incorporation of Assembly Biosciences, Inc., dated February 9, 2024 . 8-K 02/13/2024 3.1 3.3 Amended and Restated Bylaws as amended through December 12, 2024. 8-K 12/13/2024 3.1 4.1 Specimen of Common Stock Certificate. 10-K 03/20/2025 4.1 4.2 Description of Securities. 10-K 03/28/2024 4.2 4.3 Registered Warrant. 8-K 06/18/2024 4.1 4.4 Private Placement Warrant. 8-K 06/18/2024 4.2 4.5 Form of Class A Warrant. 10-Q 11/10/2025 4.1 4.6 Form of Class B Warrant. 10-Q 11/10/2025 4.2 4.7 Form of Pre-Funded Warrant. 10-Q 11/10/2025 4.3 4.8 Private Placement Class A Warrant. 10-Q 11/10/2025 4.4 4.9 Private Placement Class B Warrant. 10-Q 11/10/2025 4.5 10.1 Sublease, dated July 26, 2023, by and between Arsenal Biosciences, Inc., as Sublandlord, and Assembly Biosciences, Inc., as Subtenant. 10-Q 11/08/2023 10.1 10.2 First Amendment to Sublease, dated December 30, 2024, by and between Arsenal Biosciences, Inc. and Assembly Biosciences, Inc. 8-K 01/03/2025 10.1 10.3‡ Option, License and Collaboration Agreement, dated October 15, 2023, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 10/17/2023 10.1 10.4‡ First Amendment to Option, License and Collaboration Agreement, dated December 19, 2024, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 12/19/2024 10.1 10.5‡ Common Stock Purchase Agreement, dated October 15, 2023, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 10/17/2023 10.2 10.6 Amendment No. 1 to Common Stock Purchase Agreement, dated June 17, 2024, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 06/18/2024 10.3 10.7‡ Investor Rights Agreement, dated October 15, 2023, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 10/17/2023 10.3 10.8 Amendment No. 1 to Investor Rights Agreement, dated June 17, 2024, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 06/18/2024 10.4 10.9# Amended and Restated Employment Agreement, dated December 12, 2022, between Assembly Biosciences, Inc. and Jason A. Okazaki. 10-K 03/22/2023 10.7 10.10# Employment Agreement, dated May 1, 2020, between Assembly Biosciences, Inc. and William E. Delaney IV, Ph.D., effective as of May 27, 2020. 10-K 02/25/2021 10.12 10.11# Employment Agreement, dated November 8, 2023, between Assembly Biosciences, Inc. and Anuj Gaggar, M.D., Ph.D. 10-K 03/28/2024 10.11 64 Exhibit Number Description of Document Registrant’s Form Dated Exhibit No. Filed Herewith 10.12# Employment Agreement, dated February 10, 2022, between Assembly Biosciences, Inc. and Nicole S. White, Ph.D., effective as of February 16, 2022. 10-K 03/28/2024 10.12 10.13# 2010 Equity Incentive Plan. S-1/A 10/4/2010 10.14 10.14# Assembly Biosciences, Inc. Amended and Restated 2014 Stock Incentive Plan. 8-K 06/06/2016 10.1 10.15# Omnibus Amendment to Assembly Biosciences, Inc. Stock Incentive Plans. 10-Q 05/08/2020 10.2 10.16# Form of Notice of Stock Option Grant and Stock Option Agreement under the Amended and Restated 2014 Stock Incentive Plan. 10-K 03/22/2023 10.12 10.17# Form of Restricted Stock Unit Award Notice and Restricted Stock Unit Award Agreement under the Amended and Restated 2014 Stock Incentive Plan. 10-Q 11/01/2017 10.1 10.18# Assembly Biosciences, Inc. 2017 Inducement Award Plan. 10-Q 08/09/2017 10.1 10.19# Form of Notice of Stock Option Grant and Stock Option Agreement under the 2017 Inducement Award Plan. 10-Q 08/09/2017 10.2 10.20# Form of Restricted Stock Unit Award Notice and Restricted Stock Unit Award Agreement under the 2017 Inducement Award Plan. 10-Q 08/09/2017 10.3 10.21# Assembly Biosciences, Inc. Amended and Restated 2018 Stock Incentive Plan. 8-K 06/03/2024 10.1 10.22# Amendment No. 1 to Assembly Biosciences, Inc. Amended and Restated 2018 Stock Incentive Plan. 8-K 06/09/2025 10.1 10.23# Amendment No. 2 to Assembly Biosciences, Inc. Amended and Restated 2018 Stock Incentive Plan. 8-K 06/09/2025 10.2 10.24# Form of Notice of Stock Option Grant and Stock Option Agreement under the 2018 Stock Incentive Plan. 10-K 03/22/2023 10.22 10.25# Form of Restricted Stock Unit Award Notice and Restricted Stock Unit Award Agreement under the 2018 Stock Incentive Plan. 8-K 06/01/2018 10.3 10.26# Form of Stock Appreciation Right Award Agreement for Non-U.S. Grantees under the Assembly Biosciences, Inc. 2018 Stock Incentive Plan. 8-K 10/12/2018 10.4 10.27# Form of Performance-Based Stock Appreciation Right Award Agreement for Non-U.S. Grantees under the Assembly Biosciences, Inc. 2018 Stock Incentive Plan. 10-K 03/11/2022 10.27 10.28# Assembly Biosciences, Inc. Second Amended and Restated 2018 Employee Stock Purchase Plan. 8-K 06/03/2024 10.2 10.29# Amendment No. 1 to Assembly Biosciences, Inc. Second Amended and Restated 2018 Employee Stock Purchase Plan. 8-K 06/09/2025 10.3 10.30# Assembly Biosciences, Inc. 2019 Inducement Award Plan. 10-Q 11/07/2019 10.4 10.31# Form of Notice of Stock Option Grant and Stock Option Agreement under the 2019 Inducement Award Plan. 10-Q 11/07/2019 10.5 10.32# Assembly Biosciences, Inc. 2020 Inducement Award Plan. 10-Q 05/08/2020 10.3 10.33# Form of Notice of Stock Option Grant and Stock Option Agreement under the 2020 Inducement Award Plan. 10-Q 05/08/2020 10.4 10.34# Form of Restricted Stock Unit Award Notice and Restricted Stock Unit Award Agreement under the 2020 Inducement Award Plan. 10-Q 05/08/2020 10.5 65 Exhibit Number Description of Document Registrant’s Form Dated Exhibit No. Filed Herewith 10.35 Securities Purchase Agreement, dated June 16, 2024, by and between Assembly Biosciences, Inc. and the Purchaser. 8-K 06/18/2024 10.1 10.36 Securities Purchase Agreement, dated June 17, 2024, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 06/18/2024 10.2 10.37 Securities Purchase Agreement, dated August 8, 2025, by and between Assembly Biosciences, Inc. and Gilead Sciences, Inc. 8-K 08/11/2025 10.1 10.38# Assembly Biosciences, Inc. 2024 Corporate Bonus Plan. 8-K 03/15/2024 10.1 19.1 Assembly Biosciences, Inc. Insider Trading Policy. 10-K 03/20/2025 19.1 21.1 List of Subsidiaries of Assembly Biosciences, Inc. 10-K 03/20/2025 21.1 23.1 Consent of Independent Registered Public Accounting Firm. X 24.1 Power of Attorney (included on signature page). X 31.1 Certification of the Principal Executive Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. X 31.2 Certification of the Principal Financial Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. X 32.1** Certification of the Principal Executive Officer Pursuant to 18 U.S.C. Section 1350 as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. X 32.2** Certification of the Principal Financial Officer Pursuant to 18 U.S.C. Section 1350 as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. X 97.1# Clawback Policy. 10-K 03/28/2024 97.1 101.INS Inline XBRL Instance Document-the instance document does not appear in the Interactive Data File as its XBRL tags are embedded within the Inline XBRL document. 101.SCH Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Document. 104 Cover Page Interactive Data File, formatted in Inline XBRL (included as Exhibit 101) † The schedules to this exhibit have been omitted pursuant to Item 601(a)(5) of Regulation S-K. ‡ Portions of this exhibit have been omitted pursuant to Item 601(b)(10)(iv) of Regulation S-K. # Represents management contracts or compensatory plans or arrangements. ** The certification attached as Exhibit 32.1 that accompanies this Annual Report on Form 10-K is to be deemed furnished and shall not be deemed “filed” with the SEC and is not to be incorporated by reference into any filing of Assembly Biosciences, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Annual Report on Form 10-K, irrespective of any general incorporation language contained in such filing. Item 16. Form 10-K Summary None. 66 SIGNA TURES In accordance with Section 13 or 15(d) of the Securities Exchange Act, the Registrant caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. ASSEMBLY BIOSCIENCES, INC. Date: March 19, 2026 By: /s/ Jason A. Okazaki Name: Jason A. Okazaki Title: Chief Executive Officer and President POWER OF ATTORNEY KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Jason A. Okazaki and John O. Gunderson, jointly and severally, his or her attorneys-in-fact, each with the power of substitution, for him or her in any and all capacities, to sign any amendments to this report, and to file the same, with exhibits thereto and other documents in connection therewith with the Securities and Exchange Commission, hereby ratifying and confirming all that each of said attorneys-in-fact, or his or her substitute or substitutes may 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 by the following persons on behalf of the registrant in the capacities and on the dates indicated. Signature Title Date /s/ Jason A. Okazaki Chief Executive Officer, President and Director March 19, 2026 Jason A. Okazaki (Principal Executive Officer) /s/ Jeanette M. Bjorkquist VP, Finance March 19, 2026 Jeanette M. Bjorkquist (Principal Financial Officer and Principal Accounting Officer) /s/ William R. Ringo, Jr. Chairman of the Board March 19, 2026 William R. Ringo, Jr. /s/ Anthony E. Altig Director March 19, 2026 Anthony E. Altig /s/ Tomas Cihlar, Ph.D. Director March 19, 2026 Tomas Cihlar, Ph.D. /s/ Gina Consylman Director March 19, 2026 Gina Consylman /s/ Robert D. Cook II Director March 19, 2026 Robert D. Cook II /s/ Sir Michael Houghton, Ph.D. Director March 19, 2026 Sir Michael Houghton, Ph.D. /s/ Lisa R. Johnson-Pratt, M.D. Director March 19, 2026 Lisa R. Johnson-Pratt, M.D. /s/ Susan Mahony, Ph.D. Director March 19, 2026 Susan Mahony, Ph.D. /s/ John G. McHutchison, A.O., M.D. Director March 19, 2026 John G. McHutchison, A.O., M.D. 67 ASSEMBLY BIOSCIENCES, INC. FINANCIAL S TATEMENTS Page Report of Independent Registered Public Accounting Firm (PCAOB ID: 42 ) F- 2 Consolidated Balance Sheets as of December 31, 2025 and 2024 F- 4 Consolidated Statements of Operations and Comprehensive Loss for the Years Ended December 31, 2025 and 2024 F- 5 Consolidated Statements of Changes in Stockholders’ Equity for the Years Ended December 31, 2025 and 2024 F- 6 Consolidated Statements of Cash Flows for the Years Ended December 31, 2025 and 2024 F- 7 Notes to Consolidated Financial Statements F- 8 F- 1 Report of Independent Registered Public A ccounting Firm To the Stockholders and the Board of Directors of Assembly Biosciences, Inc. Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Assembly Biosciences, Inc. (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive loss, changes in stockholders’ equity and cash flows for each of the two years in the period ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles. Basis for Opinion These financial statements are the responsibility of the Company‘s management. Our responsibility is to express an opinion on the Company’s financial statements 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 audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the financial 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 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 financial statements. We believe that our audits provide a reasonable basis for our opinion. Critical Audit Matter The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the critical audit matter 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. F- 2 Collaboration Agreement with Gilead Sciences, Inc. Description of the Matter As described in Note 8 to the consolidated financial statements, in July 2025, the Company entered into a letter agreement related to its 2023 Gilead Collaboration Agreement, which provided reimbursement to the Company for certain nonclinical study activities. The Company determined the letter agreement represents a contract modification within the scope of the revenue from contracts with customers guidance. The Company concluded there is a single combined performance obligation for research and development services during the remaining collaboration term and will recognize revenue over time using a cost-based input method. Additionally, in December 2025, Gilead exercised its option to exclusively license the Company's helicase-primase inhibitor (HPI) program. The Company determined that Gilead’s exercise of the option represents a distinct performance obligation within the scope of the revenue from contracts with customers guidance. The Company recognized the revenue at a point in time upon the transfer of the license to Gilead. Auditing the Company’s accounting for the contract modification and option exercise required increased audit effort due to the complex and judgmental nature of evaluating the terms and assumptions under the agreements and determining the appropriate accounting under the revenue recognition guidance. How We Addressed the Matter in Our Audit To test the conclusions that the July 2025 modification and the December 2025 option exercise were accounted for appropriately, our audit procedures included, among others, reviewing the letter agreement and reviewing the option exercise notice and related communications, and evaluating whether management’s accounting positions considered all relevant facts and terms. We further evaluated management’s technical accounting analyses, including the identification of performance obligation, determination of the transaction price, and assessment of the timing of revenue recognition, and assessed whether management appropriately considered and applied the relevant accounting guidance and interpretations. /s/ Ernst & Young LLP We have served as the Company’s auditor since 2015. San Jose, California March 19, 2026 F- 3 ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED B ALANCE SHEETS (In thousands except for share amounts and par value) As of December 31, 2025 2024 ASSETS Current assets Cash and cash equivalents $ 58,450 $ 38,344 Marketable securities 189,656 73,735 Accounts receivable from collaboration with a related party 974 — Prepaid expenses and other current assets 5,469 3,424 Total current assets 254,549 115,503 Property and equipment, net 221 284 Operating lease right-of-use (ROU) assets 2,508 3,069 Other assets 312 312 Total assets $ 257,590 $ 119,168 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities Accounts payable $ 1,171 $ 585 Accrued research and development expenses 2,387 2,273 Other accrued expenses 7,749 6,862 Deferred revenue from a related party - short-term 36,904 37,622 Operating lease liabilities - short-term 569 461 Total current liabilities 48,780 47,803 Deferred revenue from a related party - long-term — 35,378 Operating lease liabilities - long-term 2,059 2,628 Total liabilities 50,839 85,809 Commitments and contingencies Stockholders' equity Preferred stock, $ 0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding — — Common stock, $ 0.001 par value; 150,000,000 shares authorized as of December 31, 2025 and December 31, 2024; 15,855,329 and 7,457,240 shares issued and outstanding as of December 31, 2025 and December 31, 2024, respectively 16 7 Additional paid-in capital 1,038,823 859,488 Accumulated other comprehensive loss ( 41 ) ( 211 ) Accumulated deficit ( 832,047 ) ( 825,925 ) Total stockholders' equity 206,751 33,359 Total liabilities and stockholders' equity $ 257,590 $ 119,168 See Accompanying Notes to the Consolidated Financial Statements F- 4 ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED STATEMENTS OF OPER ATIONS AND COMPREHENSIVE LOSS (In thousands except for share and per share amounts) Year Ended December 31, 2025 2024 Collaboration revenue from a related party $ 72,303 $ 28,520 Operating expenses Research and development 64,813 55,933 General and administrative 19,608 18,007 Total operating expenses 84,421 73,940 Loss from operations ( 12,118 ) ( 45,420 ) Other income Interest and other income, net 5,996 5,573 Total other income 5,996 5,573 Loss before income taxes ( 6,122 ) ( 39,847 ) Income tax expense — 330 Net loss $ ( 6,122 ) $ ( 40,177 ) Other comprehensive loss Unrealized gain (loss) on marketable securities 170 ( 130 ) Comprehensive loss $ ( 5,952 ) $ ( 40,307 ) Net loss per share, basic and diluted $ ( 0.55 ) $ ( 6.69 ) Weighted average common shares outstanding, basic and diluted 11,210,934 6,004,560 See Accompanying Notes to the Consolidated Financial Statements F- 5 ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED STATEMENTS OF CHA NGES IN STOCKHOLDERS’ EQUITY (In thousands except for share amounts) Common Stock Additional Accumulated Other Total Shares Amount Paid-in Capital Comprehensive Loss Accumulated Deficit Stockholders' Equity Balance as of December 31, 2023 5,482,752 $ 5 $ 826,921 $ ( 81 ) $ ( 785,748 ) $ 41,097 Issuance of common stock under at-the-market (ATM) equity offering program, net of issuance costs 152,666 — 2,030 — — 2,030 Issuance of common stock and warrants in a registered direct offering, net of issuance costs 634,500 1 9,661 — — 9,662 Issuance of common stock and warrants in a private placement to a related party, net of issuance costs 1,119,999 1 17,601 — — 17,602 Issuance of common stock upon exercise of stock options 514 — 5 — — 5 Issuance of common stock under Employee Stock Purchase Plan (ESPP) 14,937 — 150 — — 150 Issuance of common stock for settlement of restricted stock units (RSUs) 51,872 — — — — — Unrealized loss on marketable debt securities — — — ( 130 ) — ( 130 ) Stock-based compensation — — 3,120 — — 3,120 Net loss — — — — ( 40,177 ) ( 40,177 ) Balance as of December 31, 2024 7,457,240 $ 7 $ 859,488 $ ( 211 ) $ ( 825,925 ) $ 33,359 Issuance of common stock under ATM equity offering program, net of issuance costs 161,645 1 1,921 — — 1,922 Issuance of common stock, pre-funded warrants and warrants in an underwritten offering, net of issuance costs 5,591,840 6 123,594 — — 123,600 Issuance of common stock and warrants in a private placement to a related party, net of issuance costs 2,295,920 2 42,783 — — 42,785 Issuance of common stock upon exercise of warrants 255,103 — 5,510 — — 5,510 Issuance of common stock under ESPP 69,320 — 725 — — 725 Issuance of common stock upon exercise of stock options 5,406 — 125 — — 125 Issuance of common stock for settlement of RSUs 18,855 — — — — — Unrealized gain on marketable debt securities — — — 170 — 170 Stock-based compensation — — 4,677 — — 4,677 Net loss — — — — ( 6,122 ) ( 6,122 ) Balance as of December 31, 2025 15,855,329 $ 16 $ 1,038,823 $ ( 41 ) $ ( 832,047 ) $ 206,751 See Accompanying Notes to the Consolidated Financial Statements F- 6 ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED STATEM ENTS OF CASH FLOWS (In thousands) Year Ended December 31, 2025 2024 Cash flows from operating activities Net loss $ ( 6,122 ) $ ( 40,177 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 129 129 Stock-based compensation 4,677 3,120 Net accretion of investments in marketable debt securities ( 2,346 ) ( 3,658 ) Non-cash rent expense 851 1,417 Realized gain on investments in marketable debt securities ( 3 ) — Changes in operating assets and liabilities: Accounts receivable from collaboration ( 974 ) 43 Prepaid expenses and other current assets ( 2,045 ) 73 Accounts payable 586 124 Accrued research and development expenses 114 1,388 Other accrued expenses 887 1,118 Deferred revenue from a related party ( 36,096 ) ( 13,294 ) Operating lease liabilities ( 751 ) ( 1,400 ) Net cash used in operating activities ( 41,093 ) ( 51,117 ) Cash flows from investing activities Proceeds from maturities of marketable securities 116,432 130,700 Purchases of marketable securities ( 229,834 ) ( 90,501 ) Purchases of property and equipment ( 66 ) ( 28 ) Net cash (used in) provided by investing activities ( 113,468 ) 40,171 Cash flows from financing activities Proceeds from the issuance of common stock, pre-funded warrants and warrants in an underwritten offering, net of issuance costs 123,600 — Proceeds from the issuance of common stock and warrants in private placements to a related party, net of issuance costs 42,785 17,602 Proceeds from the exercise of warrants 5,510 — Proceeds from the issuance of common stock under ATM equity offering program, net of issuance costs 1,922 2,030 Proceeds from the issuance of common stock under ESPP 725 150 Proceeds from the exercise of stock options 125 5 Proceeds from the issuance of common stock and warrants in a registered direct offering, net of issuance costs — 9,662 Net cash provided by financing activities 174,667 29,449 Net increase in cash and cash equivalents 20,106 18,503 Cash and cash equivalents at the beginning of the year 38,344 19,841 Cash and cash equivalents at the end of the year $ 58,450 $ 38,344 Supplemental non-cash investing and financing activities Operating lease liabilities arising from obtaining ROU assets $ — $ 1,966 See Accompanying Notes to the Consolidated Financial Statements F- 7 ASSEMBLY BIOSCIENCES, INC. Notes to Consolidated Financial Statements Note 1 - Nature of Business Overview Assembly Biosciences, Inc. (together with its subsidiaries, Assembly or the Company), incorporated in Delaware in October 2005, is a biotechnology company developing innovative therapeutics targeting serious viral diseases with the potential to improve the lives of patients worldwide. The Company's pipeline includes multiple clinical-stage investigational therapies, including: (1) two long-acting helicase-primase inhibitors (HPI) for the treatment of recurrent genital herpes; (2) an orally bioavailable hepatitis delta virus entry inhibitor; and (3) a highly potent next-generation capsid assembly modulator designed to disrupt the replication cycle of hepatitis B virus (HBV) at several key points. The Company's pipeline also includes a novel, oral broad-spectrum non-nucleoside polymerase inhibitor (NNPI) for the treatment of transplant-related herpesviruses, which is currently undergoing studies to enable a regulatory filing, and it has additional research programs against multiple antiviral targets. In December 2025, pursuant to the collaboration with Gilead Sciences, Inc. (Gilead), Gilead exercised its option to license the Company's HPI program, including its long-acting investigational candidates ABI-1179 (1179) and ABI-5366 (5366). For additional information see Note 8 - Collaboration Agreements. The Company operates in one segment and is headquartered in South San Francisco, California (s ee Note 13 - Segment Reporting). Liquidity The Company has not derived any revenue from product sales to date and currently has no approved products. Once a product has been developed, it will need to be approved for sale by the U.S. Food and Drug Administration (FDA) or an applicable foreign regulatory agency. Since the Company’s initial public offering, its operations have been financed through the sale of equity securities and payments related to collaboration agreements. The Company has incurred losses from operations since inception and expects to continue to incur substantial losses for the next several years as it continues its product development efforts. The Company intends to obtain any additional funding it requires through strategic relationships, public or private equity or debt financings, grants or other arrangements. The Company cannot assure such funding will be available on reasonable terms, if at all. As of December 31, 2025, the Company held cash, cash equivalents and marketable securities of $ 248.1 million . Management believes the Company currently has sufficient funds to meet its operating requirements beyond one year from the date these consolidated financial statements are issued. Note 2 - Summary of Significant Accounting Policies and Recent Accounting Pronouncements Basis of Presentation These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant estimates inherent in the preparation of the accompanying consolidated financial statements include estimates for revenue recognition, including the standalone selling price (SSP) for the allocation of transaction price to performance obligations and cost-based inputs, as well as estimates of costs incurred but not yet invoiced for research and development accruals. F- 8 The Company’s estimates could be affected by external conditions, including those unique to the Company and general economic conditions. It is reasonably possible these external factors could have an effect on the Company’s estimates and could cause actual results to differ materially from those estimates and assumptions. Other Risks and Uncertainties U.S. and global financial markets have experienced and may continue to experience volatility and disruption due to macroeconomi c and geopolitical events such as rising inflation, changes in interest rates to combat inflation, the war between Russia and Ukraine, the conflicts in the Middle East, including the recent hostilities involving Iran, and in Venezuela, tensions between China and Taiwan, as well as tariffs or the imposition and enforceability of tariffs, trade wars, barriers or restrictions, or threats of such actions and the related uncertainty thereof, including uncertainties regarding the ability to obtain refunds for previously paid tariffs that have subsequently been invalidated. The Company cannot predict at this time to what extent, if at all, it and its employees, contract research organizations (CROs), vendors and/or collaborators could potentially be negatively impacted by these events. Cash and Cash Equivalents All highly liquid investments with original maturities of three months or less at the time of purchase are considered to be cash equivalents. All of the Company’s cash equivalents have liquid markets and high credit ratings. Investments in Marketable Securities The Company has designated its investments in marketable securities as available-for-sale and measures these securities at their respective fair values. The Company reviews all available-for-sale securities at each period end to determine if they remain available-for-sale based on their current intent and ability to sell the security if it is required to do so. Marketable securities are classified as short-term or long-term based on the maturity date and their availability to meet current operating requirements. Marketable securities that mature in one year or less from the consolidated balance sheet date are classified as short-term available-for-sale securities, while marketable securities with maturities in one year or beyond one year from the consolidated balance sheet date are classified as long-term. The Company periodically reviews its marketable securities for declines in fair value below the amortized cost basis to determine whether the impairment, if any, is due to credit-related or other factors. This review includes the credit worthiness of the security issuers, the severity of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not the Company will be required to sell the securities before the recovery of the amortized cost basis. Unrealized gains and losses on available-for-sale securities are reported in other comprehensive loss, and as a component of stockholders' equity until their disposition, with the exception of unrealized losses believed to be related to credit losses which are recognized as an allowance for credit losses on the consolidated balance sheet with the corresponding charge in other income in the period the impairment occurs. Impairment assessments are made at the individual security level each reporting period. The Company elected to exclude accrued interest receivable from the amortized cost basis of its available-for-sale debt securities and to not measure an allowance for credit losses for accrued interest receivable. To date, there have been no credit-related declines in value or other impairments of the Company’s investments in marketable securities. Realized gains and losses from the sale of marketable securities, if any, are calculated using the specific-identification method. Leases All of the Company’s leases are operating leases for facilities and equipment. The Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines if an arrangement is or contains a lease at inception or modification of the arrangement. Operating leases with a duration greater than one year are included in operating lease ROU assets, operating lease liabilities - short-term, and operating lease liabilities - long-term in the Company’s consolidated balance sheets. The Company elected the short-term lease exception policy, permitting it to not apply the recognition requirements to leases with terms of less than one year (short-term leases) for all classes of assets. Operating lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The incremental borrowing rate represents the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over F- 9 the term of a lease. The Company considers a lease term to be the noncancelable period that it has the right to use the underlying asset, including any periods where it is reasonably assured the Company will exercise the option to extend the contract. Periods covered by an option to extend are included in the lease term if the lessor controls the exercise of that option. The operating lease ROU assets also include any lease payments made and exclude lease incentives. Lease expense is recognized on a straight-line basis over the expected lease term. Variable lease expenses are recorded when incurred. The Company has elected not to separate lease and non-lease components for its leased assets and accounts for all lease and non-lease components of its agreements as a single lease component. Impairment of Long-Lived Assets The Company monitors the carrying value of long-lived assets, including ROU operating lease assets, for potential impairment and tests the recoverability of such assets whenever events or changes in circumstances indicate the carrying amounts may not be recoverable. If a change in circumstance occurs, the Company performs a test of recoverability by comparing the carrying value of the asset or asset group to its undiscounted expected future cash flows. If cash flows cannot be separately and independently identified for a single asset, the Company will determine whether impairment has occurred for the group of assets for which the Company can identify the projected cash flows. If the carrying values are in excess of undiscounted expected future cash flows, the Company measures any impairment by comparing the fair value of the asset or asset group to its carrying value. There was no impairment of long-lived assets during the years ended December 31, 2025 and 2024 . Fair Value Measurements The Company follows accounting guidance on fair value measurements for financial instruments measured on a recurring basis, as well as for certain assets and liabilities that are initially recorded at their estimated fair values. Fair value is defined as the exit price, or the amount that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company uses the following three-level hierarchy that maximizes the use of observable inputs and minimizes the use of unobservable inputs to value its financial instruments: Level 1: Observable inputs such as unadjusted quoted prices in active markets for identical instruments. Level 2: Quoted prices for similar instruments that are directly or indirectly observable in the marketplace. Level 3: Significant unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. Financial instruments measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement in its entirety requires the Company to make judgments and consider factors specific to the asset or liability. The use of different assumptions and/or estimation methodologies may have a material effect on estimated fair values. Accordingly, the fair value estimates disclosed or initial amounts recorded may not be indicative of the amount the Company or holders of the instruments could realize in a current market exchange. The carrying amounts of cash equivalents and marketable securities approximate their fair value based upon quoted market prices. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts which approximate their fair value due to their liquid or short-term nature, such as cash, accounts receivable, accounts payable and accrued expenses. Revenue Recognition and Accounts Receivable from Collaboration The Company analyzes its collaboration arrangements to assess whether such arrangements, or transactions between arrangement participants, involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities or are more akin to a vendor-customer relationship. In making this evaluation, the Company considers whether the activities of the collaboration are considered to be distinct and deemed to be within the scope of the collaborative arrangement accounting standard and those that are more reflective of a vendor-customer relationship and, therefore, within the scope of the revenue with contracts with customers accounting standard. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. F- 10 For elements of collaboration arrangements that are not accounted for pursuant to the revenue from contracts with customers accounting standard, an appropriate recognition method is determined and applied consistently, generally by analogy to the revenue from contracts with customers accounting standard. Amounts related to transactions with a counterparty in a collaborative arrangement that is not a customer are presented on a separate line item from revenue recognized from contracts with customers, if any, in the Company’s consolidated statements of operations and comprehensive loss. Under certain agreements under the scope of the collaborative arrangements accounting standard, the Company has been reimbursed for a portion of its research and development expenses or participates in the cost-sharing of such research and development expenses. Such reimbursements and cost-sharing arrangements are reflected as a reduction of research and development expense in the Company’s consolidated statements of operations and comprehensive loss. For arrangements or transactions between arrangement participants determined to be within the scope of the contracts with customers accounting standard, the Company evaluates the term of the arrangement and recognizes revenue when the customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company applies the following five-step model in order to determine this amount: (1) identification of the contract(s) with a customer; (2) identification of the performance obligations in the contract, including whether they are distinct in the context of the contract; (3) measurement of the transaction price, including the constraint on variable consideration; (4) allocation of the transaction price to the performance obligations; and (5) recognition of revenue when (or as) the Company satisfies each performance obligation. Amounts of variable consideration are included in the transaction price to the extent it is probable a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. The Company has provided standard indemnification and protection of licensed intellectual property for its customers. These provisions are part of assurance the licenses meet the agreements, representations and are not obligations to provide goods or services. The Company only applies the five-step model to contracts when it is probable the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company must develop assumptions that require judgment to determine the estimated relative SSP of each performance obligation identified in the contract. The Company then allocates the total transaction price to each performance obligation based on the SSP of each performance obligation. The Company recognizes the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied as revenue. Contract modifications, defined as changes in the scope or price (or both) of a contract that are approved by the parties to the contract, such as a contract amendment, exist when the parties to a contract approve a modification that either creates new, or changes existing, enforceable rights and obligations of the parties to the contract. The Company accounts for contract modifications using one of the following methods depending on facts and circumstances: (i) as a separate contract if the modification adds distinct goods or services and the price reflects the SSP of those additional goods or services; (ii) as a termination of the existing contract and creation of a new contract if the remaining goods or services are distinct from those transferred before the modification; or (iii) as a cumulative catch-up adjustment to the original contract if the remaining goods or services are not distinct from those transferred before the modification. Licenses If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from license fees based on the relative value prescribed to the license compared to the total value of the arrangement. The revenue is recognized when the license is transferred to the collaborator and the collaborator is able to use and benefit from the license. For licenses that are not distinct from other obligations identified in the arrangement, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. If the combined performance obligation is satisfied over time, the Company applies an appropriate method of measuring progress for purposes of recognizing revenue from license fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. F- 11 Research and Development Services The promises under the Company’s agreements may include research and development services to be performed by the Company on behalf of the counterparty. If these services are determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes the transaction price allocated to these services as revenue over time based on an appropriate measure of progress when the performance by the Company does not create an asset with an alternative use and the Company either has received or has an enforceable right to payment for the performance completed to date. If these services are determined not to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes the transaction price allocated to the combined performance obligation as the related performance obligations are satisfied. Customer Options If an arrangement contains customer options, the Company evaluates whether the options are material rights because they allow the customer to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The identification of a material right, and if identified as a material right, the allocation of the transaction price to it, is based on the SSP, which is determined using assumptions regarding estimated costs, discount rates, post-option development timeline, the probability of technical and regulatory success and the probability the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised or expires. If the options are deemed not to be a material right, they are considered marketing offers which are excluded as performance obligations at the outset of the arrangement. Development and Regulatory Milestone Payments Depending on facts and circumstances, the Company may record revenues from certain milestones in a reporting period before the milestone is achieved if the Company concludes achievement of the milestone is probable and recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods. The Company records a corresponding contract asset when this conclusion is reached. Milestone payments that have not been included in the transaction price to date are fully constrained. The Company re-evaluates the probability of achievement of such milestones and any related constraint each reporting period. The Company adjusts its estimate of the overall transaction price, including the amount of collaborative revenue that was recorded, if necessary. Sales-based Milestone and Royalty Payments The Company’s customers may be required to pay the Company sales-based milestone payments or royalties on future sales of commercial products. The Company recognizes revenues related to sales-based milestone and royalty payments upon the later to occur of (i) achievement of the collaborator’s underlying sales or (ii) satisfaction of any performance obligation(s) related to these sales, in each case assuming the Company’s licensed intellectual property is deemed to be the predominant item to which the sales-based milestones and/or royalties relate. The Company receives payments from its customers based on billing schedules established in the contract. Upfront payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under the arrangement. If the related performance obligation is expected to be satisfied within the next twelve months, these amounts will be classified in current liabilities. The Company recognizes a contract asset relating to its conditional right to consideration that is not subject to a constraint. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. A net contract asset or liability is presented for each contract with a customer. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. At December 31, 2025 , all accounts receivable from collaboration with a related party are deemed collectible. There were no accounts receivable from collaboration as of December 31, 2024 . Warrants and Pre-Funded Warrants The Company determines the accounting classification of warrants it issues as either liability or equity-classified based on an assessment of the warrant’s specific terms. The assessment considers whether the warrants are freestanding F- 12 financial instruments, whether the warrants meet the definition of a liability and whether the warrants meet all the requirements for equity classification. Equity classified warrants are accounted for using a relative fair value allocation method, with fair values determined at issuance using a Black-Scholes model. Stock-Based Compensation The Company measures stock-based compensation to employees and board members at fair value on the grant date of the award. The fair value of RSUs is determined based on the number of shares granted and the quoted market price of the Company’s common stock on the date of grant. The fair value of performance stock units (PSUs), which include awards with performance conditions and market conditions, are determined as follows: (i) PSUs with performance conditions are measured based on the fair value of the award on the grant date, the date performance targets are established, and is expensed over the requisite service period for each separately vesting tranche when achievement of the performance condition becomes probable, and (ii) PSUs with market conditions are measured based on the grant-date fair value of the award and is expensed over the derived service period regardless of whether the underlying market condition is met. The Company estimates the fair value of stock option grants that do not contain market-based vesting conditions using the Black-Scholes option pricing model. The assumptions used in estimating the fair value of these awards, such as expected term, expected dividend yield, volatility and risk-free interest rate, represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. The Company calculates the weighted average expected term of options using the simplified method where permitted by accounting guidance for stock-based compensation when there is limited history of relevant stock option exercise activity. The Company uses an expected dividend yield of zero as the Company currently does not intend to pay dividends in the foreseeable future. The Company calculates the expected volatility based on the Company’s historical stock prices. The risk-free interest rate assumption is based on the rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the stock option being valued. If stock-based awards are granted in contemplation of or shortly before a planned release of material nonpublic information, and such information is expected to result in a material increase in the Company’s share price, the Company considers whether an adjustment to the observable market price is required when estimating fair values. Compensation cost is recognized as expense on a straight-line basis over the requisite service period of the award. Stock-based awards with graded vesting schedules are recognized using the accelerated attribution method on a straight-line basis over the requisite service period for each separately vesting portion of the award. Forfeitures are recognized when they occur. The Company assesses the probability of the performance conditions being met on a continuous basis and is also required to make estimates as to the probability of achieving the specific performance conditions. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease compensation expense, which could be material to the Company’s consolidated results of operations. Research and Development Expense and Accruals Research and development costs include personnel-related costs, outside contracted services including clinical study costs, facilities costs, fees paid to consultants, milestone payments prior to FDA approval, license fees prior to FDA approval, professional services, travel costs, dues and subscriptions, depreciation and materials used in clinical trials and research and development and costs incurred under the Company’s collaboration agreements. Research and development costs are expensed as incurred unless there is an alternative future use in other research and development projects. Payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods or services are received. Such payments are evaluated for current or long-term classification based on when they will be realized or consumed. The Company records expenses related to clinical studies and manufacturing development activities based on its estimates of the services received and efforts expended pursuant to contracts with multiple CROs and manufacturing vendors that conduct and manage these activities on its behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract, and may result in uneven payment flows. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of subjects and F- 13 the completion of clinical study milestones. In amortizing or accruing service fees, the Company estimates the time period over which services will be performed, enrollment of subjects, number of sites activated and the level of effort expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company will adjust the accrued or prepaid expense balance accordingly. To date, there have been no material differences from the Company’s estimates to the amounts actually incurred. The Company has entered and may continue to enter into license agreements to access and utilize certain technology. In each case, the Company evaluates if the license agreement results in the acquisition of an asset or a business. To date, none of the Company’s license agreements have been considered to be acquisitions of businesses. For asset acquisitions, the upfront payments to acquire such licenses, as well as any future milestone payments, are immediately recognized as research and development expense when paid, provided there is no alternative future use of the rights in other research and development projects. These license agreements may also include contingent consideration in the form of cash payments to be made for future milestone events. The Company assesses whether such contingent consideration meets the definition of a derivative and to date the Company has determined that such contingent consideration are not derivatives. Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company establishes a valuation allowance if it is more likely than not the deferred tax assets will not be realized based on an evaluation of objective verifiable evidence. The Company recognizes and measures tax benefits from uncertain tax positions only if it is more likely than not the tax position will be sustained in an audit, including resolution of any related appeals or litigation processes. The tax benefit recognized for a particular tax position is based on the largest amount that is more than 50% likely to be realized upon ultimate settlement. Significant judgment is required to evaluate uncertain tax positions. The Company evaluates uncertain tax positions on a regular basis. The evaluations are based on a number of factors, including changes in facts and circumstances, changes in tax law, correspondence with tax authorities during the course of the audit, and effective settlement of audit issues. The provision for income taxes includes the effects of any accruals which the Company believes are appropriate. It is the Company’s policy to recognize interest and penalties related to income tax matters in income tax expense. In July 2025, the U.S. enacted tax reform legislation through the One Big Beautiful Bill Act (OBBBA). Some of the provisions of the new tax law affecting corporations include but are not limited to current deduction of domestic research expenses, increasing the limit of the deduction of interest expense deduction to thirty percent of earnings before interest, tax, depreciation and amortization, and one hundred percent bonus depreciation on eligible property acquired after January 19, 2025. The Company has evaluated the impact the new tax law had on its financial condition and results of operations. The impact of the tax law changes from the OBBBA is included in the Company’s consolidated financial statements. Net Loss per Share Basic net loss per common share excludes dilution and is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per common share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity unless inclusion of such shares would be anti-dilutive. Diluted net loss per share is the same as basic net loss per share in the years reported, since the effects of potentially dilutive securities are antidilutive given the net loss for each year presented. F- 14 A reconciliation of the numerators and the denominators of the basic and diluted net loss per common share computations is as follows (in thousands, except for share and per share amounts): Year Ended December 31, 2025 2024 Numerator: Net loss $ ( 6,122 ) $ ( 40,177 ) Denominator: Weighted average common shares outstanding - basic and diluted 11,210,934 6,004,560 Net loss per share - basic and diluted $ ( 0.55 ) $ ( 6.69 ) Securities excluded from the computation of diluted net loss per share because including them would have been antidilutive are as follows: December 31, 2025 2024 Warrants to purchase common stock 9,487,477 814,000 Options to purchase common stock 1,193,442 942,193 Common stock subject to purchase under ESPP 6,093 9,386 Unvested RSUs 85,583 52,222 Unvested PSUs 240,832 15,832 Total 11,013,427 1,833,633 In August 2025, the Company sold pre-funded warrants to purchase up to 1,040,820 shares of common stock (see Note 6 - Stockholders' Equity). The pre-funded warrants are exercisable at $ 0.001 per share. The shares of common stock into which the pre-funded warrants may be exercised are considered outstanding for purposes of computing earnings per share because the shares may be issued for little or no consideration, they are fully vested, and are exercisable after the original issuance date. Comprehensive Loss Comprehensive loss is comprised of net loss and adjustments for the change in unrealized gains and losses on investments in available-for-sale marketable securities. The Company displays comprehensive loss and its components in the consolidated statements of operations and comprehensive loss, net of tax effects if any. Concentrations of Risk Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts as of and at times during the year ended December 31, 2025 exceeded federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. F- 15 Supplier Risk Certain materials and key components the Company utilizes in its operations are obtained through single suppliers. Since the suppliers of key components and materials must be named in a New Drug Application filed with the FDA for a product, significant delays can occur if the qualification of a new supplier is required. If delivery of material from the Company’s suppliers were interrupted for any reason, the Company may be unable to supply any of its product candidates for clinical trials. Customer Risk During the year ended December 31, 2025, 100 % of the Company's collaboration revenue was recognized from a related party, Gilead, under the Gilead Collaboration Agreement (see Note 8 - Collaboration Agreements). If the collaboration with Gilead does not result in the successful development and commercialization of products or if Gilead terminates the Gilead Collaboration Agreement, the Company may not receive any future payments under the collaboration. Recently Adopted Accounting Standards In December 2023, the Financial Accounting Standards Board (the FASB) issued ASU 2023-09 , Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09). The update requires a public business entity to disclose, on an annual basis, a tabular rate reconciliation using both percentages and currency amounts, broken out into specified categories with certain reconciling items further broken out by nature and jurisdiction to the extent those items exceed a specified threshold. In addition, all entities are required to disclose income taxes paid, net of refunds received disaggregated by federal, state/local, and foreign and by jurisdiction if the amount is at least 5% of total income tax payments, net of refunds received. The Company adopted ASU 2023-09 on a prospective basis during the year ended December 31, 2025 . See Note 10 - Income Taxes for further details. Accounting Pronouncements to Be Adopted 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 (ASU 2024-03), which requires the disaggregation of certain expense captions into specified categories in disclosures within the notes to the financial statements to provide enhanced transparency into the expense captions presented on the face of the income statement. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027, with early adoption permitted, and may be applied either prospectively or retrospectively to financial statements issued for reporting periods after the effective date of ASU 2024-03 or retrospectively to any or all prior periods presented in the financial statements. The Company does not expect the potential impact of adopting ASU 2024-03 to have a material impact on its disclosures. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements (ASU 2025-11), which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. The ASU provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years, with early adoption permitted. The Company does not expect the impact of adopting ASU 2025-11 to have a material impact on its financial statements. Note 3 - Related Party In October 2023, the Company entered into the Option, License and Collaboration Agreement (Gilead Collaboration Agreement), and a Common Stock Purchase Agreement and an Investor Rights Agreement (collectively, the Gilead Equity Agreements) with Gilead. Following the Company entering into the Gilead Equity Agreements, and as of December 31, 2025, Gilead is considered a related party based on its ownership of the Company's common stock. Gilead Equity Agreements In June 2024, the Company entered into a Securities Purchase Agreement with Gilead for the issuance and sale of 179,500 shares of common stock and a warrant to purchase up to 179,500 shares of common stock in a private F- 16 placement (the June 2024 Private Placement). This transaction, which generated aggregate gross proceeds of $ 2.8 million, was executed concurrently with the June 2024 Registered Direct Offering (as defined below). See Note 6 - Stockholders' Equity for additional details. Also in June 2024, the Gilead Equity Agreements were amended. The amendments did not have an impact on the Company’s consolidated financial statements. In December 2024, Gilead exercised its right under the Gilead Equity Agreements to purchase additional shares of common stock from the Company at a purchase price of $ 21.37 per share, for aggregate proceeds of $ 20.1 million, resulting in Gilead owning 29.9 % of the Company's then-outstanding voting common stock. In August 2025, the Company entered into a Securities Purchase Agreement with Gilead for the issuance and sale of 2,295,920 shares of common stock and accompanying Class A and Class B warrants to purchase up to an aggregate of 2,295,920 shares of common stock in a private placement (collectively, the August 2025 Private Placement). This transaction, which generated aggregate gross proceeds of $ 45.0 million, was executed concurrently with the August 2025 Underwritten Offering (as defined below). See Note 6 - Stockholders' Equity for additional details. Gilead Collaboration Agreement In December 2024, the Company and Gilead entered into the First Amendment to the Gilead Collaboration Agreement, which restructured the timing of specific options exercisable in the agreement and the fees payable to the Company to support an accelerated development plan for ABI-6250 (6250), under which the Company received a non-refundable payment of $ 10.0 million. In July 2025, the Company entered into a letter agreement with Gilead under which Gilead has agreed to reimburse the Company up to $ 1.5 million for certain nonclinical study activities, subject to the terms and conditions set forth in the agreement. The letter agreement does not amend any terms of the Gilead Collaboration Agreement. In December 2025, Gilead exercised its combined option to obtain an exclusive license to the Company's HPI program, including 5366 and 1179. Upon exercise of the option, the Company received an opt-in payment of $ 35.0 million. As of December 31, 2025, the Company recorded $ 1.0 million in accounts receivable from collaboration on the consolidated balance sheet for reimbursable costs incurred under the Gilead Collaboration Agreement. The Company recognized $ 72.3 million and $ 28.5 million of collaboration revenue under the Gilead Collaboration Agreement during the years ended December 31, 2025 and 2024, respectively. See Note 8 - Collaboration Agreement for additional details. Note 4 - Investments in Marketable Securities Investments in marketable available-for-sale securities consisted of the following (in thousands): December 31, 2025 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Cash equivalents Money market fund $ 57,994 $ — $ — $ 57,994 Total cash equivalents 57,994 — — 57,994 Short-term marketable securities Corporate debt securities 37,329 34 — 37,363 Asset-backed securities 11,970 19 — 11,989 U.S. treasury securities 123,267 170 — 123,437 Commercial paper 16,858 9 — 16,867 Total short-term marketable securities 189,424 232 — 189,656 Total cash equivalents and marketable securities $ 247,418 $ 232 $ — $ 247,650 F- 17 December 31, 2024 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Cash equivalents Money market fund $ 29,066 $ — $ — $ 29,066 U.S. treasury securities 8,437 — — 8,437 Total cash equivalents 37,503 — — 37,503 Short-term marketable securities Corporate debt securities 20,971 20 ( 3 ) 20,988 U.S. treasury securities 48,077 40 — 48,117 Commercial paper 4,625 5 — 4,630 Total short-term marketable securities 73,673 65 ( 3 ) 73,735 Total cash equivalents and marketable securities $ 111,176 $ 65 $ ( 3 ) $ 111,238 Short-term marketable securities held as of December 31, 2025 and 2024 had contractual maturities of less than one year . The realized gains on investments in marketable debt securities for the year ended December 31, 2025 were not material. There were no realized gains and losses for the years ended December 31, 2024. There were no investments in an unrealized loss position as of December 31, 2025. As of December 31, 2024, investments which were in an unrealized loss position were not material and generally due to interest rate fluctuations, as opposed to declines in credit quality. The Company determined it has the intent and ability to hold all marketable securities that have been in a continuous loss position until recovery of their amortized cost basis, which may be until maturity. As a result, the Company did not recognize any credit losses related to its investments and all unrealized gains and losses on available-for-sale securities are recorded in accumulated other comprehensive loss on the consolidated balance sheets during the years ended December 31, 2025 and 2024. Accrued interest receivable was $ 1.5 million and $ 0.4 million as of December 31, 2025 and 2024, respectively, and was recorded in prepaid expenses and other current assets on the consolidated balance sheets. The Company did not write off any accrued interest receivable during the years ended December 31, 2025 and 2024. Fair Value Measurement The following tables presents the Company’s financial assets measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): December 31, 2025 Level 1 Level 2 Level 3 Fair Value Cash equivalents Money market fund $ 57,994 $ — $ — $ 57,994 Total cash equivalents 57,994 — — 57,994 Short-term marketable securities Corporate debt securities — 37,363 — 37,363 Asset-backed securities — 11,989 — 11,989 U.S. treasury securities — 123,437 — 123,437 Commercial paper — 16,867 — 16,867 Total short-term marketable securities — 189,656 — 189,656 Total assets measured at fair value $ 57,994 $ 189,656 $ — $ 247,650 F- 18 December 31, 2024 Level 1 Level 2 Level 3 Fair Value Cash equivalents Money market fund $ 29,066 $ — $ — $ 29,066 U.S. treasury securities — 8,437 — 8,437 Total cash equivalents 29,066 8,437 — 37,503 Short-term marketable securities Corporate debt securities — 20,988 — 20,988 U.S. treasury securities — 48,117 — 48,117 Commercial paper — 4,630 — 4,630 Total short-term marketable securities — 73,735 — 73,735 Total assets measured at fair value $ 29,066 $ 82,172 $ — $ 111,238 Money market funds are highly liquid and actively traded marketable securities that generally transact at a stable $1.00 net asset value representing its estimated fair value. The Company estimates the fair value of its U.S. and foreign corporate debt securities, U.S. treasury securities and U.S. and foreign commercial paper by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs. There were no transfers between Level 1, Level 2 or Level 3 for any of the years presented. Note 5 – Other Accrued Expenses Other accrued expenses consist of the following (in thousands): December 31, 2025 2024 Accrued expenses: Accrued compensation $ 7,523 $ 6,478 Accrued professional fees and other 226 384 Total accrued expenses $ 7,749 $ 6,862 Note 6 - Stockholders’ Equity The Company is authorized to issue 5,000,000 shares of preferred stock as of December 31, 2025 and 2024. As of December 31, 2025 and 2024 , no shares of preferred stock were issued and outstanding. The Company is authorized to issue 150,000,000 shares of common stock as of December 31, 2025 and 2024. Reverse Stock Split In January 2024, the Company's stockholders approved a reverse stock split of its common stock at a range of ratios between 1-for-7 to 1-for-17 , and the Company's board of directors approved the implementation of the reverse stock split at a ratio of 1-for-12 (the Reverse Stock Split). The Reverse Stock Split was undertaken to enable the Company to regain compliance with the minimum bid price requirement for continued listing on the Nasdaq Global Select Market, as referenced in the deficiency notice received from the Nasdaq Listing Qualifications Department in September 2023. The Reverse Stock Split became effective in February 2024, at which time the Company regained compliance with the minimum bid price requirement. As of the effective time of the Reverse Stock Split, every 12 issued and outstanding shares of the Company’s common stock was automatically reclassified into one issued and outstanding share of the Company’s common stock. This reduced the number of shares outstanding from 65.8 million shares to 5.5 million shares. No fractional shares of common stock were issued in connection with the Reverse Stock Split and all fractional shares were rounded down to the nearest whole share with respect to outstanding shares of common stock. Any holders of common stock who would F- 19 have otherwise received a fractional share of common stock pursuant to the Reverse Stock Split, received cash in lieu of the fractional share. The Reverse Stock Split did not affect the par value of the common stock. The Company's authorized shares of common stock remained at 150,000,000 and its authorized shares of preferred stock remained at 5,000,000 . Sale of Common Stock and Warrants At-The-Market Offering In November 2024, the Company entered into a sales agreement under which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $ 75.0 million through "at-the-market" offerings (the ATM), pursuant to its shelf registration statement on Form S-3 (File No. 333-270760), which became effective in April 2023. During the year ended December 31, 2025, the Company issued and sold 161,645 shares of its common stock under the ATM, for which the Company received net proceeds of $ 1.9 million , after deducting commissions, fees and expenses. During the year ended December 31, 2024, the Company issued and sold 152,666 shares of its common stock under the ATM, for which the Company received net proceeds of $ 2.0 million , after deducting commissions, fees and expenses. Registered Direct Offering In June 2024, the Company issued and sold 634,500 shares of common stock and a warrant to purchase up to 634,500 shares of common stock in a registered direct offering pursuant to its shelf registration statement on Form S-3 on file with the SEC (the June 2024 Registered Direct Offering). The common stock and warrant were sold at a combined offering price of $ 15.46 per share for aggregate gross proceeds to the Company of $ 9.8 million. After deducting issuance costs, net proceeds totaled $ 9.7 million. Underwritten Offering In August 2025, the Company issued and sold an aggregate of 5,591,840 shares of common stock and pre-funded warrants to purchase up to 1,040,820 shares of common stock, together with accompanying 3,316,330 Class A and 3,316,330 Class B warrants to purchase up to an aggregated total of 6,632,660 shares of common stock in an underwritten offering (the August 2025 Underwritten Offering). The combined price per share of common stock with the accompanying Class A and Class B warrants was $ 19.60 , while the combined price per pre-funded warrant with accompanying Class A and Class B warrants was $ 19.599 . The offering generated aggregate gross proceeds to the Company of $ 130.0 million. After deducting issuance costs, net proceeds totaled $ 123.6 million. Private Placements In June 2024, the Company issued and sold 179,500 shares of common stock and a warrant to purchase up to 179,500 shares of common stock under the June 2024 Private Placement with Gilead (as defined in Note 3 - Related Party) . This transaction was executed concurrently with the June 2024 Registered Direct Offering pursuant to anti-dilution provisions in the Investor Rights Agreement, with the common stock and warrant sold at the same combined offering price of $ 15.46 per share for aggregate gross proceeds to the Company of $ 2.8 million. After deducting issuance costs, net proceeds totaled $ 2.7 million. In December 2024, Gilead exercised its right under the Gilead Equity Agreements to purchase an additional 940,499 shares of common stock from the Company at a purchase price of $ 21.37 per share, which represents a 35 % premium to the 30 trading day volume weighted average price immediately prior to the date of purchase. The Company received aggregate proceeds of $ 20.1 million, of which $ 5.2 million was determined to be a premium on the purchase of the Company’s common stock and allocated to the single combined performance obligation under the Gilead Collaboration Agreement (see Note 8 - Collaboration Agreements). The fair value of Gilead's common stock purchase was $ 14.9 million. In August 2025, the Company entered into the August 2025 Private Placement (as defined in Note 3 - Related Party) with Gilead, which involved the issuance and sale of 2,295,920 shares of common stock and accompanying 1,147,960 Class A and 1,147,960 Class B warrants to purchase up to an aggregate of 2,295,920 shares of common stock in a private placement. This transaction was executed concurrently with the August 2025 Underwritten Offering. F- 20 The combined price per share of common stock with the accompanying Class A and Class B warrants was $ 19.60 , generating aggregate gross proceeds of $ 45.0 million. After deducting issuance costs, net proceeds totaled $ 42.8 million. These warrants have the same exercise price and terms as the warrants sold in the August 2025 Underwritten Offering. Warrants The following warrants and pre-funded warrants to purchase shares of the Company's common stock were issued and outstanding: December 31, Issue Date Exercisable Date Expiration Date Exercise Price per Share 2025 2024 6/16/2024 6/16/2024 6/18/2029 $ 17.00 634,500 634,500 6/17/2024 6/17/2024 6/18/2029 $ 17.00 179,500 179,500 8/11/2025 8/11/2025 No expiration $ 0.001 1,040,820 — 8/11/2025 8/11/2025 8/11/2030 (1) $ 21.60 4,209,187 — 8/11/2025 11/15/2026 (2) 12/31/2026 (2) $ 21.60 4,464,290 — 10,528,297 814,000 (1) These Class A warrants will expire 30 days following the public announcement that the Company completed enrollment (of at least 200 patients total) in the ABI-5366 Phase 2 clinical study if prior to August 11, 2030. (2) These Class B warrants will be cancelled if the Company publicly announces the receipt of at least $ 75.0 million in the aggregate of non-dilutive capital in connection with a collaboration agreement prior to November 15, 2026. There were 255,103 Class A warrants exercised during December 31, 2025. No warrants were exercised during December 31, 2024. The Company’s warrants and pre-funded warrants are classified as a component of permanent stockholders’ equity within additional paid-in capital and were recorded at their respective issuance date using a relative fair value allocation method. Of the total proceeds from the issuance of warrants in the August 2025 Underwritten Offering and the August 2025 Private Placement, $ 16.4 million was allocated to pre-funded warrants, $ 24.6 million to Class A warrants and $ 1.2 million to Class B warrants. The warrants and pre-funded warrants are equity classified because they are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, do not embody an obligation for the Company to repurchase its shares, permit the holders to receive a fixed number of common shares upon exercise, are indexed to the Company’s common stock and meet the equity classification criteria. In addition, such warrants and pre-funded warrants do not provide any guarantee of value or return. Holders of all warrants and pre-funded warrants cannot exercise any portion of the warrants to the extent they would beneficially own more than the limits defined in the warrant agreements. The exercise price and number of shares of the Company's common stock issuable upon the exercise of the warrants are subject to adjustment in the event of any stock dividends and distributions, stock splits, stock combinations or stock reclassifications, as described in the respective warrant agreements. Under certain circumstances, the warrants may be exercised on a “cashless” basis. Note 7 - Stock-Based Compensation Equity Incentive Plans In June 2025, the Company's stockholders approved an amendment to the Assembly Biosciences, Inc. Amended and Restated 2018 Stock Incentive Plan (the 2018 Plan) , which increased the aggregate number of shares of common stock reserved under the 2018 Plan to 1,703,333 . As of December 31, 2025, the Company had awards outstanding under the following shareholder approved plans: 2010 Equity Incentive Plan (the 2010 Plan), which has been frozen since 2016; the Assembly Biosciences, Inc. F- 21 Amended and Restated 2014 Stock Incentive Plan (the 2014 Plan); and the 2018 Plan. Shares of common stock underlying awards forfeited under the 2010 Plan on or after June 2, 2016 become available for issuance under the 2014 Plan. As of December 31, 2025, the Company also had awards outstanding under the following plans that are not approved by shareholders: the Assembly Biosciences, Inc. 2017 Inducement Award Plan, the Assembly Biosciences, Inc. 2019 Inducement Award Plan, and the Assembly Biosciences, Inc. 2020 Inducement Award Plan. The Company issues new shares of common stock to settle options exercised and vested RSUs or PSUs. The Company also issues new shares of common stock in connection with purchases of shares of common stock by eligible employees under the ESPP. Stock Plan Activity Stock Options The following tables summarize the stock option activity and related information for 2025 (in thousands, except for share and per share amounts): Number of Shares Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Total Intrinsic Value (in thousands) Outstanding as of December 31, 2024 942,193 $ 54.24 7.3 $ 1,383 Granted 275,225 11.14 Exercised ( 5,743 ) 22.58 Forfeited ( 11,584 ) 109.69 Expired ( 6,649 ) 123.26 Outstanding as of December 31, 2025 1,193,442 $ 43.53 7.0 $ 17,215 Options vested and exercisable as of December 31, 2025 714,173 $ 64.31 5.9 $ 6,934 Options expected to vest as of December 31, 2025 1,193,442 $ 43.53 7.0 $ 17,215 Year Ended December 31, 2025 2024 Weighted-average grant-date fair value of options granted $ 8.23 $ 10.04 Total intrinsic value of options exercised $ 44 $ 2 The fair value of stock options granted during the periods indicated was estimated using the Black-Scholes option pricing model, based on the following assumptions: Year Ended December 31, 2025 2024 Exercise price $ 10.62 - $ 24.61 $ 12.90 - $ 16.75 Expected volatility 81.1 % - 86.4 % 79.1 % - 86.9 % Risk-free rate 3.70 % - 4.42 % 3.50 % - 4.57 % Expected term (years) 5.5 - 7.0 5.5 - 7.5 Expected dividend yield 0 % 0 % F- 22 RSUs The following tables summarize RSU activity and related information for 2025 (in thousands, except for share and per share amounts): Number of RSUs Weighted Average Fair Value Per RSU at Grant Price Nonvested as of December 31, 2024 52,222 $ 17.99 Granted 53,933 10.69 Vested ( 18,855 ) 21.87 Forfeited ( 1,717 ) 11.85 Nonvested as of December 31, 2025 85,583 $ 12.65 Year Ended December 31, 2025 2024 Total fair value of RSUs vested and settled $ 412 $ 1,131 Total intrinsic value of RSUs vested and settled $ 203 $ 228 PSUs The following tables summarize PSU activity and related information for 2025 (in thousands, except for share and per share amounts): Number of PSUs Weighted Average Fair Value Per PSU at Grant Price Nonvested as of December 31, 2024 15,832 $ 20.88 Granted 225,000 17.24 Nonvested as of December 31, 2025 240,832 $ 17.48 Year Ended December 31, 2025 2024 Total fair value of PSUs vested and settled $ — $ 1,029 Total intrinsic value of PSUs vested and settled $ — $ 488 ESPP In June 2025, the Company's stockholders approved an amendment to the ESPP, which increased the aggregate number of shares of common stock available for purchase by employees up to 225,000 shares at a discount to the market price. Eligible employees may participate through payroll deductions of up to 15 % of such employee’s compensation for each pay period subject to annual statutory limits. Eligible employees can purchase the Company’s common stock at the end of a predetermined offering period at 85 % of the lower of the fair market value at the beginning or end of the offering period. Under the ESPP, the offering periods end on the last business day occurring on or before May 14 or November 14. The ESPP is compensatory and results in stock-based compensation expense. In May and November 2025, employees purchased 34,696 and 34,624 shares of common stock, respectively, under the ESPP. In May and November 2024, employees purchased 7,252 and 7,685 shares of common stock, respectively, under the ESPP. As of December 31, 2025, 86,097 shares of common stock are available for future sale under the Company’s ESPP. F- 23 The fair value of ESPP purchase rights were not material for any period presented. Stock-Based Compensation Expense The Company recognized stock-based compensation expense included in the consolidated statement of operations and comprehensive loss for the years presented (in thousands), classified by expense type and award type: Year Ended December 31, 2025 2024 Research and development $ 2,628 $ 1,531 General and administrative 2,049 1,589 Total stock-based compensation expense $ 4,677 $ 3,120 Year Ended December 31, 2025 2024 Stock options $ 2,387 $ 2,511 RSUs 427 368 PSUs 1,552 139 ESPP 311 102 Total stock-based compensation expense $ 4,677 $ 3,120 As of December 31, 2025, there was $ 4.6 million of total unrecognized stock-based compensation cost related to outstanding unvested equity awards, which is expected to be recognized over a weighted average remaining amortization period of 1.3 years. Note 8 - Collaboration Agreements The following table presents changes in the Company’s contract liabilities under the Gilead Agreements (in thousands): Year Ended December 31, Contract liabilities: 2025 2024 Deferred revenue balance at beginning of period $ 73,000 $ 86,294 Cash received 35,233 10,000 Accounts receivable from collaboration with a related party 974 — Premium on purchase of the Company's common stock — 5,226 Revenue recognized ( 72,303 ) ( 28,520 ) Deferred revenue balance at end of period $ 36,904 $ 73,000 Less: current portion $ ( 36,904 ) $ ( 37,622 ) Deferred revenue from a related party - long-term $ — $ 35,378 Year Ended December 31, 2025 2024 Collaboration revenue from a related party recognized in the period from: Amounts included in deferred revenue from a related party at the beginning of the period $ 36,841 $ 28,271 Performance obligations satisfied in previous period $ — $ — Gilead Agreements In October 2023, the Company entered into the Gilead Collaboration Agreement and the Gilead Equity Agreements under which it received total proceeds of $ 100.0 million. Under the Gilead Collaboration Agreement, Gilead exclusively licensed to the Company its HPI program and NNPI program, while retaining opt-in rights to these programs and has an option to take an exclusive license, on a program-by-program basis, to all of the Company’s other current and future pipeline programs. During the 12-year collaboration term (subject to payment of certain F- 24 extension fees) and for a specified period thereafter, Gilead may exercise its opt-in rights, on a program-by-program basis, at one of two timepoints—completion of a certain Phase 1 study or, upon payment of a deferral fee and completion of a certain Phase 2 study for the first product within the program—upon payment of an opt-in fee ranging from $ 45.0 million to $ 125.0 million per program depending on the type of program and when the option is exercised. In December 2024, the Company and Gilead entered into the First Amendment to the Gilead Collaboration Agreement, which restructured the timing of specific options exercisable in the agreement and the fees payable to the Company to support an accelerated development plan for 6250. To facilitate this development plan, the Company received a non-refundable payment of $ 10.0 million from Gilead and the opt-in fee payable by Gilead in connection with 6250 was restructured, though it remains in the range of opt-in fees detailed above. The $ 10.0 million payment received in connection with the First Amendment to the Gilead Collaboration Agreement is creditable towards future collaboration-related payments payable by Gilead. This credit was applied toward Gilead's opt-in fee paid for the HPI program in December 2025. In July 2025, the Company entered into a letter agreement with Gilead under which Gilead has agreed to reimburse the Company up to $ 1.5 million for certain nonclinical study activities, subject to the terms and conditions set forth in the agreement. The letter agreement does not amend any terms of the Gilead Collaboration Agreement. If Gilead exercises its opt-in right to any current or future program under the collaboration, the Company is eligible to receive up to $ 330.0 million in potential regulatory and commercial milestones on that program, in addition to royalties ranging from the high single-digits to high teens, depending on the clinical stage of the program at the time of the opt-in. Following Gilead’s exercise of its option for each program, the Company may opt-in to cover 40 % of the research and development costs in the United States and share 40 % of the profits and operating loss in the United States for products within the program in lieu of receiving milestones and royalties for that program in the United States, unless the Company later opts out of the cost/profit share for the program. Prior to Gilead’s potential exercise of its opt-in, the Company will be primarily responsible for all discovery, research and development on its programs and the two Gilead-contributed programs. Following Gilead’s opt-in, Gilead will control the further discovery, research, development, and commercialization on any optioned programs , and is responsible for all related costs unless the Company opts in to share 40 % of all costs and profits in the United States. During the term, Gilead will continue to support the collaboration through extension fees of $ 75.0 million in each of the third, fifth and seventh anniversaries of the collaboration. The Gilead Collaboration Agreement is subject to termination by either party for the other party’s uncured, material breach or insolvency. Subject to certain limitations, the Company and Gilead both have certain termination for convenience rights, upon sufficient prior written notice, with respect to programs that one party in-licenses from the other (subject to Gilead’s option rights), and with respect to Gilead, for programs it has option rights to (subject to certain time limitations with respect to existing Company programs). Gilead also has a right to terminate the collaborative activities under the Gilead Collaboration Agreement at certain specified points during the collaboration term. Other customary termination rights are further provided in the Gilead Collaboration Agreement. R&D Services At the commencement of the arrangement, the Company concluded Gilead was a customer and accordingly, the Gilead Collaboration Agreement was within the scope of the revenue from contracts with customers guidance. The Company initially identified a single combined performance obligation for the discovery, research and development services (the R&D Services) consisting of a series of distinct services that are substantially the same and have the same pattern of transfer. The Company concluded the R&D Services were distinct from Gilead's right to obtain an exclusive license to any of the Company's programs as Gilead benefits from the knowledge and expertise gained from the R&D Services and the Company's know-how is not highly specialized in nature. Gilead could perform the R&D Services themselves, particularly considering Gilead contributed its HPI and NNPI programs and Gilead may continue to conduct development activities on programs being developed under the Gilead Collaboration Agreement. None of the options in the contract were deemed to be separate performance obligations as the options did not provide any discounts or other rights which would be considered a material right in the arrangement. In December 2024, Gilead exercised its right under the Gilead Equity Agreements to purchase additional shares of the Company's common stock for aggregate proceeds of $ 20.1 million, of which $ 5.2 million was determined to be a F- 25 premium on the purchase of the Company’s common stock and allocated to the single combined performance obligation under the Gilead Collaboration Agreement. In December 2024, the Company determined the First Amendment to the Gilead Collaboration Agreement represented a contract modification within the scope of the revenue from contracts with customers guidance. In July 2025, upon its execution, the Company similarly concluded the letter agreement represented a contract modification under the same guidance. For both modifications, the Company determined no new distinct performance obligations were introduced, there continues to be a single combined performance obligation consisting of a series of distinct R&D Services, and therefore, the remaining services under the modified Gilead Collaboration Agreement are distinct from the R&D Services already provided. Accordingly, the Company accounted for each modification as a termination of the existing contract and the creation of a new contract. The Company reassessed the transaction price upon each modification and recognized revenue prospectively by reassessing the transaction price and allocating it to the remaining R&D Services. The amended transaction price as a result of the modification upon entering into the letter agreement in July 2025 was determined to be $ 54.4 million , consisting of the unrecognized portion of the transaction price under the contract immediately before the modification and $ 1.5 million of variable consideration for reimbursable costs expected to be incurred pursuant to the letter agreement. The variable consideration related to the regulatory milestones has not been included in the transaction price as of December 31, 2025, as these amounts remain highly susceptible to factors outside the Company's influence. Any variable consideration related to commercial milestones and royalties will be recognized when the related sales occur pursuant to the Gilead Collaboration Agreement. The Company will reevaluate the transaction price in each reporting period as uncertain events are resolved or other changes in circumstances occur. The transaction price is reflected as collaboration revenue when realized in the Company’s consolidated statements of operations. The Company recognizes revenue over time using a cost-based input method, based on internal and external labor cost effort to perform the services, over the initial non-cancellable term of three years since this method best reflects the transfer of services to Gilead. In applying a cost-based input method of revenue recognition, the Company uses actual costs incurred relative to estimated total costs to fulfill each performance obligation. A cost-based input method of revenue recognition requires the Company to make estimates of costs to complete the performance obligation. The cumulative effect of any revisions to estimated costs to complete the performance obligation and associated variable consideration will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods. The Company recognized $ 37.3 million and $ 28.5 million of collaboration revenue for R&D Services performed under the Gilead Collaboration Agreement during the years ended December 31, 2025 and 2024, respectively. The Company incurred $ 0.1 million and $ 0.3 million in reimbursable expenses due to Gilead during the years ended December 31, 2025 and 2024, respectively. HPI Program License In December 2025, Gilead exercised its option to exclusively license the Company's HPI program for the treatment of recurrent genital herpes, including 5366 and 1179. Under the terms of the Gilead Collaboration Agreement, the Company received a $ 35.0 million payment in connection with Gilead’s exercise of its HPI program. The $ 35.0 million payment reflects a $ 45.0 million option fee, net of $ 10.0 million in accelerated funding the Company received under the First Amendment to the Gilead Collaboration Agreement, which was creditable against future payments. Gilead received an exclusive license to 5366 and 1179 and will have the sole right and responsibility for further clinical development and commercialization of the HPI program. The Company remains eligible to receive up to $ 330.0 million in regulatory and commercial milestones, as well as tiered royalties on net sales ranging from the high single-digits to low teens. The Company also has the right to opt in to share 40 % of all costs and profits in the United States (the Profit-Share) in lieu of receiving milestones and royalties for that program in the United States after receipt of a development plan and budget from Gilead; The Company has not opted into the Profit-Share as of the date of this report. F- 26 The Company determined the exclusive license granted to Gilead for the HPI program was a new contract under the contracts from customers accounting standard as it was deemed an exercise of a marketing offer made pursuant to the original terms of the Gilead Collaboration Agreement and First Amendment. The Company concluded the exclusive license granted to Gilead for the HPI program represents a distinct performance obligation because Gilead can benefit from the license together with readily available resources and its ability to sublicense the rights. The $ 35.0 million opt-in fee is included in the fixed transaction price. Variable consideration related to regulatory and commercial milestone payments, royalties and cost reimbursements are constrained because such amounts are highly susceptible to factors outside the Company's influence. The Company recognized $ 35.0 million of collaboration revenue related to the exclusive license granted for the HPI program at a point in time upon transfer of the license, when Gilead obtained the ability to use and benefit from the license, during the year ended December 31, 2025. Arbutus Biopharma Agreement In August 2020, the Company and Arbutus Biopharma Corporation (Arbutus Biopharma) entered into a Clinical Trial Collaboration Agreement (the Arbutus Biopharma Agreement) to conduct a randomized, multi-center, open-label Phase 2 clinical trial to explore the safety, pharmacokinetics and antiviral activity of the triple combination of vebicorvir (VBR), AB-729 and a nucleos(t)ide analog reverse transcriptase inhibitor (NrtI) compared to the double combinations of VBR with a NrtI and AB-729 with a NrtI. Under the Arbutus Biopharma Agreement, Assembly and Arbutus Biopharma shared responsibility for the costs of the trial equally, excluding manufacturing supply which were the burden of each company to supply their respective drugs, VBR and AB-729. Assembly was responsible for conducting this clinical trial with Arbutus Biopharma reimbursing Assembly its share of expenses. In February 2023, Assembly and Arbutus Biopharma terminated the Phase 2 clinical trial early, at the end of the 48-week on-treatment period. The Arbutus Biopharma Agreement was within the scope of the collaborative arrangements guidance as both parties were active participants and were exposed to significant risks and rewards dependent on the success of the collaborative activity. Reimbursements and cost-sharing portions from Arbutus Biopharma were reflected as a reduction of research and development expense when realized in the Company’s consolidated statements of operations. During the year ended December 31, 2024, the Company recognized research and development expenses of $ 0.3 million for net amounts refundable to Arbutus Biopharma after the final reconciliation of clinical trial costs. Amounts refundable to Arbutus Biopharma were recorded as accrued research and development expenses on the consolidated balance sheet as of December 31, 2024. Note 9 – HBV Research Agreement with Indiana University Since September 2013, the Company was party to an exclusive License Agreement with Indiana University Research and Technology Corporation (IURTC) from whom it licensed aspects of the Company’s HBV program held by IURTC. The license agreement required the Company to make milestone payments based upon the successful accomplishment of clinical and regulatory milestones. The aggregate amount of all performance milestone payments under the IURTC license agreement, if all milestones through development were met, was $ 0.8 million, with a portion having been paid. The Company was obligated to pay IURTC royalty payments based on net sales of the licensed technology as well as a portion of any sublicensing revenue Assembly received. The Company was also required to pay diligence maintenance fees each year to the extent that the royalty, sublicensing, and milestone payments to IURTC were less than such fees for that year. The Company terminated the IURTC license agreement effective April 2024. The Company paid IURTC $ 0.1 million in diligence maintenance fees during the year ended December 31, 2024 , which were included in research and development expenses in the consolidated statements of operations and comprehensive loss. F- 27 Note 10 - Income Taxes Income tax expense is as follows (in thousands): Year Ended December 31, 2025 2024 Current: State $ — $ 330 Income tax expense $ — $ 330 The Company adopted ASU 2023-09 prospectively for the year ended December 31, 2025. Prior period disclosures have not been retrospectively adjusted and may not be comparable to the current year presentation under the new standard. The reconciliation between the federal statutory tax rate applied to loss before income taxes and the Company's effective tax rate is summarized as follows (in thousands, except percentages): Year Ended December 31, 2025 Amount Percent Tax computed at federal statutory rate $ ( 1,286 ) 21.0 % State tax, net of federal income tax effect (1) ( 118 ) 1.9 % Non-taxable or nondeductible items: Permanent items 24 - 0.4 % Covered employee compensation 121 - 2.0 % Share-based payment awards 615 - 10.0 % Changes in valuation allowance ( 12,986 ) 212.1 % Tax credits: Federal research and development tax credits 17,027 - 278.1 % Changes in unrecognized tax benefits ( 3,397 ) 55.5 % Income tax expense / Effective tax rate — 0.0 % (1) State taxes in California comprise the majority (greater than 50.0%) of the tax effect in this category. The effective tax rate of the Company's provision for income taxes differs from the federal statutory rate as follows: Year Ended December 31, 2024 Statutory federal income tax rate 21.0 % State taxes, net of federal tax benefit 8.1 % Research and development tax credits 8.4 % Return to provision adjustments - 4.8 % Uncertain tax positions - 1.7 % Stock-based compensation - 8.4 % Other - 0.5 % Change in valuation allowance - 22.9 % Income taxes provision (benefit) - 0.8 % Income taxes paid, net of refunds received, were not material during the year ended December 31, 2025 . The Company paid $ 0.4 million of income taxes during the year ended December 31, 2024. F- 28 Significant components of the Company’s deferred taxes are as follows (in thousands): As of December 31, 2025 2024 Deferred tax assets: Federal and state-operating loss carryforwards $ 123,615 $ 131,994 Stock-based compensation 7,359 7,078 Capitalized research expense 29,377 35,593 Deferred revenue 9,382 18,484 Operating lease liabilities 668 782 Research and development credits 5,377 18,436 Other 32 53 Total deferred tax assets 175,810 212,420 Valuation allowance ( 175,113 ) ( 211,614 ) Deferred tax asset, net of valuation allowance $ 697 $ 806 Deferred tax liabilities: Operating lease right-of-use assets $ ( 638 ) $ ( 777 ) Other ( 59 ) ( 29 ) Total deferred tax liabilities ( 697 ) ( 806 ) Net deferred tax liability $ — $ — The Company maintains a valuation allowance on deferred tax assets due to the uncertainty regarding the ability to utilize these deferred tax assets in the future. The valuation allowance decreased by $ 36.5 million for the year ended December 31, 2025, primarily due to a reduction in the Company's research and development credits and federal and state net operating loss carryforwards resulting from an ownership change under Internal Revenue Code (IRC) Sections 382 and 383 (see below). The valuation allowance increased by $ 9.2 million for the year ended December 31, 2024, primarily due to an increase in the Company’s federal and state net operating loss carryforwards generated during the year. Net operating loss and tax credit carryforwards as of December 31, 2025 are as follows (in thousands): Amount Expiration Years Net operating losses, federal (post December 31, 2017) $ 432,835 Indefinite Net operating losses, federal (pre January 1, 2018) 67,208 2029 - 2037 Net operating loss, state (Indefinite) 880 Indefinite Net operating loss, state (Definite) 315,530 2029 - 2054 Research and development tax credits, federal 793 2040 - 2045 Research and development tax credits, state 7,521 Indefinite Pursuant to IRC Sections 382 and 383, use of the Company’s U.S. federal and state net operating loss and research and development income tax credit carryforwards may be limited in the event of a cumulative change in ownership of more than 50% within a three-year period. The Company performed an ownership change study through August 2025 and determined a change in ownership, as defined by IRC Section 382, occurred in December 2010, January 2013, October 2014 and August 2025. As a result, the Company adjusted its federal and California deferred tax assets for net operating loss and research and development carryforwards to reflect attributes which will expire due to the limitation, with a corresponding change to the valuation allowance recorded against such assets. The Company has not completed a similar analysis with respect to its other remaining state net operating loss carryforwards, which totaled $ 224.1 million as of December 31, 2025, and accordingly, it is possible additional limitations or expirations exist that have not yet been reflected. If further ownership changes occur, additional net operating loss and tax credit carryforwards could be eliminated or restricted. If eliminated, the related deferred tax asset would be removed with a corresponding reduction in the valuation allowance. F- 29 The following table summarizes activity related to the Company’s gross unrecognized tax benefits (in thousands): As of December 31, 2025 2024 Balances as of beginning of year $ 5,175 $ 4,495 Decreases related to prior year tax positions ( 3,687 ) ( 31 ) Increases related to current year tax positions 317 711 Balances as of end of year $ 1,805 $ 5,175 The unrecognized tax benefits, if recognized, would not have an impact on the Company’s effective tax rate assuming the Company continues to maintain a full valuation allowance position. Based on the prior year’s operations and experience, the Company does not expect a significant change to its unrecognized tax benefits over the next twelve months. The unrecognized tax benefits may increase or change during the next year for unexpected or unusual items that arise in the ordinary course of business. In subsequent periods, any interest and penalties related to uncertain tax positions will be recognized as a component of income tax expense. Interest and penalties related to unrecognized tax benefits were not material for the years ended December 31, 2025 and 2024. The Company files income tax returns in the U.S. federal, California and other state and foreign jurisdictions and is not currently under examination by federal, state, or local taxing authorities for any open tax years. Due to net operating loss carryforwards, all years effectively remain open for income tax examination by tax authorities in the U.S. and states in which the Company files tax returns. Note 11 - Operating Leases In August 2023, the Company entered into a sublease agreement for office and laboratory space in South San Francisco, California to serve as the Company's corporate headquarters. The sublease originally expired in October 2025 , with an option to extend through September 2029 . In December 2024, the Company amended the sublease to extend the term through September 2029 and modify the base rent payments beginning in January 2025, with scheduled annual rent increases over the remaining lease term. The Company dissolved its China subsidiary in 2024, allowing the lease for its registrational office in Shanghai to expire in March 2024. The Company also leased certain laboratory equipment accounted for as operating leases, the last of which expired in 2025. When the Company cannot determine the implicit rate in its leasing arrangements, the Company uses its incremental borrowing rate as the discount rate when measuring operating lease liabilities. The incremental borrowing rate represents an estimate of the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease within a particular currency environment. At December 31, 2025, the Company had operating lease liabilities of $ 2.6 million and ROU assets of $ 2.5 million . The following summarizes quantitative information about the Company’s operating leases (in thousands): Year Ended December 31, 2025 2024 Lease cost Operating lease cost $ 851 $ 1,417 Short-term lease cost — 1 Variable lease cost 817 727 Total lease cost, net $ 1,668 $ 2,145 As of December 31, 2025, the weighted-average remaining lease term for operating leases was 3.8 years and the weighted-average discount rate for operating leases was 10.0 % . F- 30 As of December 31, 2025, the maturities of the Company’s operating lease liabilities were as follows (in thousands): 2026 $ 806 2027 834 2028 863 2029 671 Total 3,174 Less: present value discount ( 546 ) Operating lease liabilities $ 2,628 Note 12 - Employee Benefit Plan In January 2018, the Company established a defined contribution 401(k) plan (the Plan) for all employees who are at least 21 years of age. Employees are eligible to participate in the Plan upon commencement of employment. Under the terms of the Plan, employees may make voluntary contributions as a percentage of compensation. The Plan also permits the Company to make discretionary matching contributions. The Company made discretionary matching contributions of $ 0.8 million and $ 0.7 million for the Plan during the years ended December 31, 2025 and 2024 , respectively. Note 13 - Segment Reporting The Company operates as a single operating s egment focusing on developing innovative therapeutics targeting serious viral diseases. The Company's chief oper ating decision maker (CODM) is its Chief Executive Officer and President, who reviews financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance, and allocating resources. The measure of segment profit or loss used by the CODM to evaluate performance and allocate resources is consolidated net loss as reported in the Company's consolidated statements of operations. This measure is used by the CODM to assess its cash runway and make strategic decisions about resource allocation. The CODM does not use asset measures to evaluate segment performance or make resource allocation decisions. Operating expenses include all costs necessary to operate the Company's business, primarily consisting of research and development and general and administrative expenses directly related to advancing the Company's programs. These expenses are reviewed by the CODM on a consolidated basis as part of evaluating the Company's overall financial performance. During the years ended December 31, 2025 and 2024, the Company generated all of its collaboration revenue from Gilead, who is a related party (see Notes 3 - Related Party and 8 - Collaboration Agreements). For the years ended December 31, 2025 and 2024, all of the Company's revenue and long-lived assets were in the United States. F- 31 The following table presents the significant segment expenses and other segment items regularly reviewed by the Company's CODM: Year Ended December 31, 2025 2024 Collaboration revenue from a related party $ 72,303 $ 28,520 Less: External program expenses: ABI-5366 9,353 6,215 ABI-1179 8,119 4,239 ABI-6250 5,780 6,396 ABI-4334 890 2,646 ABI-7272 (1) 2,300 — Research and discovery 8,161 8,985 Vebicorvir — ( 43 ) (2) Total external program expenses 34,603 28,438 Employee and contractor-related expenses (3) 26,729 23,819 Facility and other expenses 3,481 3,676 Total research and development 64,813 55,933 General and administrative (3) 19,608 18,007 Interest and other income, net ( 5,996 ) ( 5,573 ) Income tax expense — 330 Net loss $ ( 6,122 ) $ ( 40,177 ) (1) In October 2025, the Company transitioned its discovery and development from ABI-7423 to its parent molecule, ABI-7272, which is currently in regulatory filing-enabling preclinical studies. (2) Reflects net amounts refundable to the Company after the final reconciliation of costs of the clinical trial conducted pursuant to the Arbutus Biopharma Agreement, which was terminated in February 2023. (3) Includes stock-based compensation expense, see Note 7 - Stock-Based Compensation for further details. F- 32