Cyclerion Therapeutics, Inc. 10-K

Item 9A. Controls and Procedures. Disclosure Controls and Procedures We maintain “disclosure controls and procedures,” as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, that are designed to ensure that information required to be disclosed by us in reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms, and that such information is accumulated and communicated to our management, including our principal executive and our principal financial officers, as appropriate, to allow timely decisions regarding required disclosure. With respect to the year ended December 31, 2025, under the supervision and with the participation of our management, we conducted an evaluation of the effectiveness of the design and operations of our disclosure controls and procedures. Based upon this evaluation, our President and Chief Financial Officer have concluded that our disclosure controls and procedures were effective as of December 31, 2025 to provide reasonable assurance that the information required to be disclosed by us in this Annual Report was (a) reported within the time periods specified by SEC rules and regulations and (b) communicated to our management, including our President and Chief Financial Officer, to allow timely decisions regarding any required disclosure. Management's Report on Internal Control Over Financial Reporting Our management is responsible for establishing and maintaining adequate internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) to provide reasonable assurance regarding the reliability of our financial reporting and the preparation of consolidated financial statements for external purposes in accordance with GAAP. Internal control over financial reporting is a process designed by, or under the supervision of, our President and Chief Financial Officer, and effected by our Board of Directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that: • Pertain to the maintenance of records that accurately and fairly reflect in reasonable detail the transactions and dispositions of the assets of our company; 65 • Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that our receipts and expenditures are being made only in accordance with authorizations of our management and directors; and • Provide reasonable assurances regarding prevention or timely detection of unauthorized acquisition, use or disposition of our assets that could have a material adverse effect on our financial statements. Management assessed our internal control over financial reporting as of December 31, 2025, the end of our fiscal year. Management based its assessment on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework). Management’s assessment included evaluation of elements such as the design and operating effectiveness of key financial reporting controls, process documentation, accounting policies, and our overall control environment. Based on this assessment, management has concluded that our internal controls over financial reporting were effective as of December 31, 2025 and provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external reporting purposes in accordance with GAAP. We reviewed the results of management’s assessment with the Audit Committee of our Board of Directors. Internal control over financial reporting has inherent limitations. Internal control over financial reporting is a process that involves human diligence and compliance and is subject to lapses in judgment and breakdowns resulting from human failures. Internal control over financial reporting also can be circumvented by collusion or improper management override. Because of such limitations, there is a risk that material misstatements will not be prevented or detected on a timely basis by internal control over financial reporting. However, these inherent limitations are known features of the financial reporting process. Therefore, it is possible to design into the process safeguards to reduce, though not eliminate, this risk. Attestation Report of the Registered Public Accounting Firm This Annual Report does not include an attestation report of our independent registered public accounting firm regarding internal control over financial reporting as we are a “smaller reporting company” and “non-accelerated filer” as defined under the rules of the Securities and Exchange Commission. Changes in Internal Control over Financial Reporting There were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the fiscal year ended December 31, 2025 which have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. Inherent Limitations on Effectiveness of Internal Controls In designing and evaluating the disclosure controls and procedures, management does not expect that our internal control over financial reporting will prevent or detect all errors and all fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control systems are met. Further, the design of a control system must reflect the fact that there are resource constraints, and the benefits of controls must be considered relative to their costs. The design of any disclosure controls and procedures also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions. Our management, including our President and Chief Financial Officer, believes that our disclosure controls and procedures and internal control over financial reporting are designed to provide reasonable assurance of achieving their objectives and are effective at the reasonable assurance level. However, our management does not expect that our disclosure controls and procedures or our internal control over financial reporting will prevent all errors and all fraud. Item 9B. Other Information. (a) None 66 (b) Director and Officer Trading Arrangements None of our directors or officers adopted or terminated a Rule 10b5-1 trading arrangement or adopted or terminated a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K) during the fourth quarter ended December 31, 2025. Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections. Not applicable. 67 PART III We intend to file a definitive Proxy Statement for our 2026 Annual Meeting of Stockholders, or the Proxy Statement, with the SEC, pursuant to Regulation 14A, not later than 120 days after the end of our fiscal year. Accordingly, certain information required by Part III has been omitted under General Instruction G(3) to Form 10-K. Only those sections of the 2026 Proxy Statement that specifically address the items set forth herein are incorporated by reference. Item 10. Directors, Executive Of ficers and Corporate Governance. The information required by this Item 10 will be included in our Proxy Statement under the captions “Information Regarding the Board of Directors and Corporate Governance,” “Election of Directors,” “Executive Officers” and “Section 16(a) Beneficial Ownership Reporting Compliance” and is incorporated herein by reference. Item 11. Executiv e Compensation. The information required by this Item 11 will be included in our Proxy Statement under the captions “Executive Compensation” and “Director Compensation” and is incorporated herein by reference. Item 12. Security Ownership of Certain Beneficial Ow ners and Management and Related Stockholder Matters. The information required by this Item 12 will be included in our Proxy Statement under the captions “Security Ownership of Certain Beneficial Owners and Management” and “Securities Authorized for Issuance under Equity Compensation Plans” and is incorporated herein by reference. Item 13. Certain Relationships and Related Transactions, and Director Independence. The information required by this Item 13 will be included in our Proxy Statement under the captions “Transactions with Related Persons” and “Independence of the Board of Directors” and is incorporated herein by reference. Item 14. Principal Accou nting Fees and Services. The information required by this Item 14 will be included in our Proxy Statement under the caption “Ratification of Selection of Independent Registered Public Accounting Firm” and is incorporated herein by reference. 68 PART IV Item 15. Exhibits, Financ ial Statement Schedules. (a)(1) Financial Statements See the Index to Consolidated Financial Statements in the Financial Statements Section beginning on page F-1 of this Annual Report on Form 10-K. (a)(2) Financial Statement Schedules All financial statement schedules have been omitted as they are not required, not applicable, or the required information is included in the financial statements or notes to the financial statements. (a)(3) Exhibits EXHIBIT INDEX Exhibit No. Description 3.1 Restated Articles of Organization of Cyclerion Therapeutics, Inc. (incorporated by reference to Exhibit 4.1 to Registration Statement on Form S-8 filed on March 29, 2019) (File No. 333-230615)) 3.2 Articles of Amendment to Amended and Restated Articles of Incorporation dated May 15, 2023 (incorporated by reference to Exhibit 3.1 to Current Report on Form 8-K filed on May 15, 2023) (File No.001-38787) 3.3 Articles of Amendment to Amended and Restated Articles of Incorporation dated May 19, 2023 (incorporated by reference to Exhibit 3.1 to Current Report on Form 8-K filed on May 25, 2023) (File No. 38787) 3.4 Amended and Restated Bylaws of Cyclerion Therapeutics, Inc. (incorporated by reference to Exhibit 4.2 to Registration Statement on Form S-8 filed on March 29, 2019) (File No. 333-230615)) 4.1 # Description of Securities Registered pursuant to Section 12 of the Securities Exchange Act of 1934, as amended 10.1 Intellectual Property License Agreement, dated April 1, 2019, by and between Ironwood Pharmaceuticals, Inc. and Cyclerion Therapeutics, Inc. (incorporated by reference to Exhibit 10.6 to Current Report on Form 8-K filed on April 2, 2019 (File No. 001-38787)) 10.2 + Form of Indemnification Agreement between Cyclerion Therapeutics, Inc. and individual directors and officers (incorporated by reference to Exhibit 10.7 to Form 10 filed on January 28, 2019 (File No. 001-38787)) 10.3 + Cyclerion Therapeutics, Inc. 2019 Employee Stock Purchase Plan (incorporated by reference to Exhibit 4.3 to Registration Statement on Form S-8 filed on March 29, 2019 (File No. 333-230615)) 10.4 + Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan (incorporated by reference to Exhibit 4.4 to Registration Statement on Form S-8 filed on March 29, 2019 (File No. 333-230615)) 10.5 + Form of Stock Option Agreement under the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan (incorporated by reference to Exhibit 10.10 to Form 10 filed on March 4, 2019 (File No. 001-38787)) 10.6 + Form of Non-Employee Director Restricted Stock Agreement under the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan (incorporated by reference to Exhibit 10.11 to Form 10 filed on March 4, 2019 (File No. 001-38787)) 69 10.7 + Form of Restricted Stock Unit Agreement under the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan (incorporated by reference to Exhibit 10.12 to Form 10 filed on March 4, 2019 (File No. 001-38787)) 10.8 + Cyclerion Therapeutics, Inc. Amended and Restated 2010 Employee, Director and Consultant Equity Incentive Plan and forms of agreement thereunder (incorporated by reference to Exhibit 4.5 to Registration Statement on Form S-8 filed on March 29, 2019 (File No. 333-230615)) 10.9 * License Agreement, dated as of June 3, 2021, by and between Cyclerion Therapeutics, Inc. and Akebia Therapeutics, Inc (incorporated by reference to Exhibit 10.2 to Quarterly Report on Form 10-Q filed on July 29, 2021 (File No. 001-38787)) 10.10 * Amendment #1 to License Agreement by and between the Company and Akebia Therapeutics, Inc. dated December 13, 2024 (incorporated by reference to Exhibit 10.1 to Current Report on Form 8-K filed on December 17, 2024) 10.11 Common Stock Purchase Agreement, dated as of June 3, 2021, by and between Cyclerion Therapeutics, Inc. and the Investors named therein (incorporated by reference to Exhibit 10.1 to Registration Statement on Form S-3 filed on June 16, 2021 (File No. 333-257145)). 10.12 * Patent License Agreement, dated as of September 19, 2025, by and between Cyclerion Therapeutics, Inc. and Massachusetts Institute of Technology (incorporated by reference to Exhibit 10.1 to Quarterly Report on Form 10-Q filed on November 12, 2025 (File No. 001-38787)) 10.13 + Amendment to Original Offer Letter to Regina Graul (incorporated by reference to Exhibit 10.1 to Quarterly Report on Form 10-Q filed on August 7, 2024 (File No. 001-38787)) 10.14 *# Collaboration and Option Agreement, dated as of January 3, 2026, by and between Cyclerion Therapeutics, Inc. and Medsteer, SAS 10.15 Sales Agreement by and between Cyclerion Therapeutics, Inc. and Guggenheim Securities, LLC, dated May 7, 2025. (incorporated by reference to Exhibit 1.1 to Current Report on Form 8-K filed on May 7, 2025) (File No.001-38787) 10.16 Registration Rights Agreement, dated March 21, 2025, by and among Cyclerion Therapeutics, Inc. and the investors party thereto (incorporated by reference to Exhibit 10.2 to Current Report on Form 8-K filed on March 25, 2025) (File No.001-38787) 10.17 + Consulting Agreement with Rhonda Chicko dated August 4, 2025 (incorporated by reference to Exhibit 10.1 to Quarterly Report on Form 10-Q filed on August 5, 2025 (File No. 001-38787)) 19 # Insider Trading Prevention Policy 21.1 # List of Subsidiaries 23.1 # Consent of Ernst & Young LLP , Independent Registered Public Accounting Firm 31.1 # Certificate of Chief Executive Officer (Principal Executive Officer) pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 31.2 # Certificate of Chief Financial Officer (Principal Financial Officer) pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 32.1† Certificate of Chief Executive Officer (Principal Executive Officer) pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 32.2† Certificate of Chief Financial Officer (Principal Executive Officer) pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 97.1 Policy for the Recovery of Erroneously Awarded Compensation adopted November 30, 2023 (incorporated by reference to Exhibit 97.1 to Annual Report on Form 10-K filed on March 4, 2025 (File No. 001-38787)) 70 101.INS Inline XBRL Instance Document 101.SCH Inline XBRL Taxonomy Extension Schema Document 104 Cover Page Interactive Data File + Indicates a management contract or compensatory plan. * Certain portions of this exhibit (indicated by asterisks) have been omitted because they are not material and are the type that the Registrant treats as private or confidential. † The certifications attached as Exhibits 32.1 and 32.2 that accompany this Report, are not deemed filed with the SEC and are not to be incorporated by reference into any filing of Cyclerion Therapeutics, 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 Report irrespective of any general incorporation language contained in such filing. # Filed herewith. Item 16. Form 10-K Summary. Not applicable. 71 SIGNAT URES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrants have duly caused this report to be signed on their behalf by the undersigned, thereunto duly authorized, on March 30, 2026. CYCLERION THERAPEUTICS, INC. By: /s/ Regina Graul Regina Graul President and Chief Executive Officer POWER OF ATTORNEY KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Regina Graul and Rhonda Chicko, jointly and severally, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign this Annual Report on Form 10-K of Cyclerion Therapeutics, Inc., and any or all amendments thereto, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises hereby ratifying and confirming all that said attorneys-in-fact and agents, or his, her or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities indicated on March 30, 2026. Signature Title /s/ Regina Graul Regina Graul President, Chief Executive Officer (Principal Executive Officer) and Director /s/ Rhonda Chicko Rhonda Chicko Chief Financial Officer (Principal Financial and Accounting Officer) /s/ Errol De Souza Errol De Souza Director /s/ Peter Hecht Peter Hecht Director /s/ Michael Higgins Michael Higgins Director /s/ Steven Hyman Steven Hyman Director /s/ Dina Katabi Dina Katabi Director 72 Index to Consolidated Financial Statements of Cyclerion Therapeutics, Inc. 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 Statement of 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 the Consolidated Financial Statements F- 8 F- 1 Report of Independent Registered Public Accounting Firm To the Shareholders and the Board of Directors of Cyclerion Therapeutics, Inc. Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Cyclerion Therapeutics, Inc. (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive loss, 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. The Company's Ability to Continue as a Going Concern The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As discussed in Note 1 to the consolidated financial statements, the Company has suffered recurring losses from operations, has limited financial resources, and has stated that substantial doubt exists about the Company’s ability to continue as a going concern. Management's evaluation of the events and conditions and management’s plans regarding these matters are also described in Note 1. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. 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 Assessment of indicators of impairment of investment in Tisento Therapeutics Holdings Inc. Description of the Matter As discussed in Notes 2 and 4 to the consolidated financial statements, as of December 31, 2025, the Company had recognized an Other investment of $5.4 million which was accounted for as a financial instrument without a readily determinable fair value. Such investment was recorded using the measurement alternative for investments without readily determinable fair values, whereby the investment was measured at cost less any impairment recorded or adjustments for observable price changes. As of December 31, 2025, no impairment loss was recognized. Auditing the Company's assessment of indicators of impairment of the Other investment was complex and required significant judgment in applying our audit procedures and in the evaluation of the results of the procedures performed to determine if any impairment indicators were present. In addition, there was a significant degree of subjectivity in evaluating the relevance and reliability of the audit evidence obtained. How We Addressed the Matter in Our Audit We performed audit procedures to test management’s evaluation of events or changes in circumstances that might be indicators of impairment of the Company’s Other investment. Such procedures included, among others: (i) evaluating the appropriateness of management’s assessment of indicators of impairment; (ii) independently obtaining and assessing evidence, including from external sources, to corroborate management’s judgments and evaluating contrary evidence; (iii) reading the minutes of the Company’s Board of Directors meetings; and (iv) performing inquiries of management of Tisento Therapeutics Holdings Inc. and the Company regarding their knowledge of impairment indicators. We have served as the Company’s auditor since 2018. /s/ Ernst & Young LLP Boston, Massachusetts March 30, 2026 F- 3 Cyclerion Therapeutics, Inc. Consolidated Balance Sheets (In thousands, except share and per share data) December 31, 2025 December 31, 2024 ASSETS Current assets: Cash and cash equivalents $ 3,240 $ 3,232 Accounts receivable 1,000 556 Prepaid expenses 384 421 Other current assets 11 16 Total current assets 4,635 4,225 Other investment 5,350 5,350 Total assets $ 9,985 $ 9,575 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities: Accounts payable $ 508 $ 390 Accrued research and development costs 198 52 Accrued expenses and other current liabilities 194 283 Total current liabilities 900 725 Commitments and contingencies (Note 6) — — Stockholders' equity Preferred stock, no par value, 100,000,000 shares authorized and 351,037 shares of Series A convertible preferred stock issued and outstanding at December 31, 2025 and 2024 — — Common stock, no par value, 400,000,000 shares authorized at December 31, 2025 and 2024; 3,925,314 and 2,710,096 shares issued at December 31, 2025 and 2024, respectively; 3,821,236 and 2,545,922 shares outstanding at December 31, 2025 and 2024, respectively — — Paid-in capital 280,105 276,342 Accumulated deficit ( 271,020 ) ( 267,492 ) Total stockholders' equity 9,085 8,850 Total liabilities and stockholders' equity $ 9,985 $ 9,575 The accompanying notes are an integral part of these consolidated financial statements. F- 4 Cyclerion Therapeutics, Inc. Consolidated Statements of Operations and Comprehensive Loss (In thousands, except per share data) Year Ended December 31, 2025 2024 Revenues: Revenue from license agreement $ 1,000 $ 1,750 Revenue from purchase agreement 800 — Revenue from option agreement 274 250 Total revenues 2,074 2,000 Cost and expenses: Research and development 959 286 General and administrative 6,088 5,342 Total cost and expenses 7,047 5,628 Loss from operations ( 4,973 ) ( 3,628 ) Other income, net Interest income 128 208 Gain from settlement of account payable — 363 Gain from insurance recovery 1,317 — Total other income, net 1,445 571 Net loss $ ( 3,528 ) $ ( 3,057 ) Net loss per share: Basic and diluted net loss per share $ ( 1.11 ) $ ( 1.21 ) Weighted average shares used in calculating: Basic and diluted shares 3,181 2,518 Other comprehensive loss: Net loss $ ( 3,528 ) $ ( 3,057 ) Other comprehensive loss: Foreign currency translation adjustment loss — ( 6 ) Comprehensive loss $ ( 3,528 ) $ ( 3,063 ) The accompanying notes are an integral part of these consolidated financial statements. F- 5 Cyclerion Therapeutics, Inc. Consolidated Statement s of Stockholders’ Equity (In thousands, except share data) Common Stock Preferred Stock Paid-in Accumulated Accumulated other comprehensive Total Stockholders’ Shares Amount Shares Amount capital deficit loss equity Balance at December 31, 2023 2,474,159 $ — 351,037 $ — $ 275,717 $ ( 264,417 ) $ ( 12 ) $ 11,288 Net loss — — — — — ( 3,057 ) — ( 3,057 ) Vesting of restricted stock awards 71,763 — — — — — — — Share-based compensation expense related to issuance of stock options and restricted stock awards — — — — 625 — — 625 Foreign currency translation adjustment — — — — — — ( 6 ) ( 6 ) Release of foreign currency translation adjustment upon liquidation of a subsidiary ( 18 ) 18 — Balance at December 31, 2024 2,545,922 $ — 351,037 $ — $ 276,342 $ ( 267,492 ) $ — $ 8,850 Issuance of common stock - private placement, net of issuance cost 499,998 — — — 1,245 — — 1,245 Issuance of common stock - ATM 715,220 — — — 2,077 — — 2,077 Net loss — — — — — ( 3,528 ) — ( 3,528 ) Vesting of restricted stock awards 60,096 — — — — — — — Share-based compensation expense related to issuance of stock options and restricted stock awards — — — — 441 — — 441 Balance at December 31, 2025 3,821,236 $ — 351,037 $ — $ 280,105 $ ( 271,020 ) $ — $ 9,085 The accompanying notes are an integral part of these consolidated financial statements. F- 6 Cyclerion Therapeutics, Inc. Consolidated Statements of Cash Flows (In thousands) Year Ended December 31, 2025 2024 CASH FLOWS FROM OPERATING ACTIVITIES: Net loss $ ( 3,528 ) $ ( 3,057 ) Adjustments to reconcile net loss to net cash used in operating activities: Gain from settlement of account payable — ( 363 ) Share-based compensation expense 441 625 Changes in operating assets and liabilities: Accounts receivable ( 444 ) ( 556 ) Prepaid expenses 37 21 Other current assets 5 ( 5 ) Accounts payable 118 ( 445 ) Accrued research and development costs 146 ( 38 ) Accrued expenses and other current liabilities ( 89 ) ( 515 ) Net cash used in operating activities ( 3,314 ) ( 4,333 ) CASH FLOWS FROM FINANCING ACTIVITIES: Proceeds from ATM 2,077 — Proceeds from private placement 1,375 — Issuance costs paid for private placement ( 130 ) — Net cash provided by financing activities 3,322 — Effect of exchange rate changes on cash and cash equivalents — ( 6 ) Net increase (decrease) in cash and cash equivalents 8 ( 4,339 ) Cash and cash equivalents, beginning of period 3,232 7,571 Cash and cash equivalents, end of period $ 3,240 $ 3,232 The accompanying notes are an integral part of these consolidated financial statements. F- 7 Cyclerion Therapeutics, Inc. Notes to the Consolidated Financial Statements 1. Nature of Business Nature of Operations Cyclerion Therapeutics, Inc. (“Cyclerion”, the “Company” or “we”) became an independent public company on April 1, 2019 after Ironwood Pharmaceuticals, Inc. completed a tax-free spin-off of their sGC business. Cyclerion has one employee as of December 31, 2025 and also relies on a team of specialist consultants for its operations. Cyclerion is focused on building a new pipeline of innovative therapeutics to address serious neuropsychiatric diseases. The Company’s current strategic focus is centered on the development of a novel therapeutic approach for treatment-resistant depression (“TRD”), which represents a substantial clinical and commercial opportunity. Over the past year, the Company has refined its strategic direction toward programs that combine established pharmacologic agents with enabling technologies designed to improve precision, reproducibility, and patient outcomes. As part of this strategy, Cyclerion has evaluated multiple opportunities and prioritized CYC-126, an individualized therapy for TRD as its foundational development program. In September 2025, the Company entered into a license agreement with the Massachusetts Institute of Technology (“MIT”) for intellectual property supporting this program (see Note 11), and in January 2026 entered into a collaboration and option-to-license agreement with Medsteer SAS (“Medsteer”) to access certain technology, data assets, and technical know-how related to drug delivery and physiological monitoring. The Company is advancing development planning, regulatory strategy, and commercial positioning for this program and intends to initiate a Phase 2 proof-of-concept study in Australia in the second half of 2026. In parallel with the advancement of its neuropsychiatric strategy, Cyclerion continues to evaluate opportunities related to its legacy soluble guanylate cyclase (“sGC”) stimulator assets, including potential collaborations, monetization opportunities, or other strategic transactions designed to maximize shareholder value. Praliciguat is an orally administered, once-daily systemic sGC stimulator. On June 3, 2021, Cyclerion entered into a license agreement with Akebia Therapeutics Inc. (“Akebia”) relating to the exclusive worldwide license to Akebia of our rights to the development, manufacture, medical affairs and commercialization of pharmaceutical products containing praliciguat and other related products and forms thereof enumerated in such agreement. In 2021, Akebia paid a $ 3.0 million upfront payment to the Company upon signing of the license agreement. On December 13, 2024, Cyclerion announced that Cyclerion and Akebia have re-negotiated a mutually beneficial amendment to their exclusive license agreement for praliciguat, a systemic sGC stimulator. Under this new license amendment, Cyclerion will receive $ 1.75 million in amendment payments , of which $ 1.25 million was paid in December 2024 and an additional payment of $ 0.5 million was received in September 2025 . In addition, Akebia is responsible for all intellectual property expenses associated with praliciguat. On December 1, 2025, Akebia publicly announced that it has recently initiated (defined as first patient dosed) Phase 2 clinical trials for the treatment of focal segmental glomerulosclerosis (“FSGS”) using praliciguat. Pursuant to the terms of amendment, upon initiation of a Phase 2 clinical trial in the U.S. for a product, a $ 1.0 million development milestone payment would be due to us and it was received in February 2026. The Company is eligible to receive additional milestone cash payments of up to approximately $ 557.5 million in total potential future development, regulatory, and commercialization milestone payments for praliciguat. In exchange for a reduction in certain development milestone payments, Cyclerion is eligible to receive certain higher-tiered sales-based royalties ranging from mid-single-digits to twenty percent. Olinciguat is a Phase 2, orally administered, once-daily, vascular sGC stimulator. On July 22, 2024, the Company entered into an Option to License Agreement (the “Option Agreement”) with a third party (the “Optionee”), pursuant to which the Optionee had an option (the “Option”) to enter into an exclusive license to olinciguat for human therapeutics, subject to certain carveouts. Under the terms of the Option Agreement, the Optionee paid the Company an Option fee of $ 150,000 in August 2024 and subsequent fees totaling $ 80,000 to F- 8 extend the term of the Option Agreement. The Optionee originally could exercise the Option on or before March 20, 2025, which was ultimately extended through August 22, 2025. Thereafter, the parties had an additional 60 days to negotiate the terms of a definitive license agreement. The parties were unable to agree upon the terms of a license agreement and the Company provided notice on October 23, 2025 that it was terminating the Option Agreement. The Company is currently exploring potential license opportunities for olinciguat. Zagociguat is a clinical-stage CNS-penetrant sGC stimulator that has shown rapid improvement in cerebral blood flow, functional brain connectivity, brain response to visual stimulus, cognitive performance, and biomarkers associated mitochondrial function and inflammation in clinical studies. CY3018 is a CNS-targeted sGC stimulator that preferentially localizes to the brain and has a pharmacology profile that suggests its potential for the treatment of neuropsychiatric diseases and disorders. On July 28, 2023, the Company sold Zagociguat and CY3018 to Tisento Therapeutics, Inc. (“Tisento”), a newly formed private company focused on their development, in exchange for $ 8.0 million in cash consideration, $ 2.4 million as reimbursement for certain operating expenses related to zagociguat and CY3018 for the period between signing and closing of the transaction, and 10 % of all of Tisento ’s parent’s outstanding equity securities (“Tisento Parent”). Cyclerion GmbH, a wholly owned subsidiary, was incorporated in Zug, Switzerland on May 3, 2019. The functional currency is the Swiss franc. Cyclerion GmbH was liquidated and de-registered in May 2024. Cyclerion Securities Corporation, a wholly owned subsidiary, was incorporated in Massachusetts on November 15, 2019 and was granted securities corporation status in Massachusetts. Stock Purchase Agreement In March 2023, the Company entered into a stock purchase agreement with the Company's former Chief Executive Officer (the “CEO”) pursuant to which he invested $ 5 million in cash for 225,000 shares of common stock and 351,037 shares of Series A Convertible Preferred Stock of the Company at a price of $ 8.68 per share (after giving effect to the 1-for-20 reverse stock split the Company implemented on May 15, 2023). The Series A Convertible Preferred Stock is convertible into shares of the Company's common stock on a one-to-one basis. The closing of the equity investment took place on May 19, 2023, and (to comply with Nasdaq listing requirements) the Company's shareholders approved such convertibility on July 19, 2023. 2025 Equity Private Placement On March 21, 2025 , the Company entered into a Stock Purchase Agreement (the “2025 Equity Private Placement”) for a private placement of 499,998 shares of the Company’s common stock, at a purchase price of $ 2.75 per share for total gross proceeds of approximately $ 1.375 million. The closing of the 2025 Equity Private Placement occurred on March 25, 2025. T he Company incurred transaction costs of $ 0.1 million for the 2025 Equity Private Placement. The Shares issued were not registered under the Securities Act of 1933, as amended, or any state securities laws and will be issued pursuant to the exemption from registration provided for under Section 4(a)(2) of the Securities Act as a transaction not involving a public offering. In connection with the 2025 Equity Private Placement, the Company entered into a Registration Rights Agreement with the investors, dated March 21, 2025, pursuant to which the Company agreed to register the resale of the Shares pursuant to a registration statement which was filed with the SEC and declared effective by the SEC on May 15, 2025. At-the-Market Offering On February 4, 2025, the Company filed a Registration Statement on Form S-3 (the “Shelf”) with the Securities and Exchange Commission (the “SEC”) in relation to the registration of common stock, preferred stock, warrants and units of any combination thereof for an aggregate initial offering price not to exceed $ 25.0 million. The Registration Statement was declared effective by the SEC in February 2025. On May 7, 2025, the Company and Guggenheim Securities, LLC (“Guggenheim Securities”) entered into a Sales Agreement (the “Sales Agreement”), pursuant to which the Company may offer and sell shares of common stock, no par value per share (the “Shares”), having an aggregate offering price of up to $ 20,000,000 from time to F- 9 time through or to Guggenheim Securities, acting as the Company’s agent, subject to the application of General Instruction I.B.6 of Form S-3 (“Instruction I.B.6”) pertaining to primary offerings by certain registrants, including the Company. The Company has provided Guggenheim Securities with customary indemnification rights, and t he Company will pay Guggenheim Securities cash commission of 3.0 % of the gross proceeds of the Shares sold under the Sales Agreement. During the year ended December 31, 2025, the Company sold 715,220 shares of its common stock for net proceeds of $ 2.1 million under the Sales Agreement, after deducting commissions paid to Guggenheim Securities of $ 0.1 million. Basis of Presentation The consolidated financial statements and the related disclosures have been prepared in accordance with U.S. generally accepted accounting principles . In the opinion of management, the consolidated financial statements reflect all normal recurring adjustments considered necessary for a fair presentation of the Company’s financial position and the results of its operations for the fiscal years presented. The consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries, Cyclerion Securities Corporation and Cyclerion GmbH which was dissolved in May 2024. All significant intercompany accounts and transactions have been eliminated in the preparation of the accompanying consolidated financial statements. Going Concern At each reporting period, in accordance with Accounting Standards Codification ("ASC") 205-40, Going Concern, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash and cash equivalent balances. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. In performing its analysis, management excluded certain elements of its operating plan that cannot be considered probable. Under ASC 205-40, the future receipt of potential funding from future partnerships, equity or debt issuances, certain cost reduction measures and the potential milestones from the Akebia agreement cannot be considered probable at this time because these plans are not entirely within the Company’s control and/or have not been approved by the Board of Directors as of the date of these consolidated financial statements. The Company expects that its cash and cash equivalents as of December 31, 2025, will be sufficient to fund operations through mid-2026 , however the Company will need to obtain additional funding to sustain operations as it expects to continue to generate operating losses for the foreseeable future. The Company's expectation to generate negative operating cash flows in the future and the need for additional funding to support its planned operations, raise substantial doubt regarding the Company’s ability to continue as a going concern. Management's plans to alleviate the conditions that raise substantial doubt include reduced spending, and the pursuit of additional capital. Management has concluded the likelihood that its plan to successfully obtain sufficient funding, or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company’s ability to continue as a going concern. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and F- 10 satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above. 2. Summary of Significant Accounting Policies Segment Information The Company operates and manages its business as a single segment for the purposes of assessing performance and making operating decisions. The Company’s president and chief executive officer, who is the chief operating decision maker ("CODM"), reviews the Company’s financial information on a consolidated basis for purposes of evaluating financial performance and allocating resources. When evaluating the Company’s financial performance, the CODM regularly reviews net loss, non-operating expenses and operating expenses excluding non-cash stock based compensation expense. Variable Interest Entities The Company reviews each legal entity in which it has a financial interest to determine whether or not the entity is a variable interest entity or VIE. If the entity is a VIE, the Company assesses whether or not it is the primary beneficiary of that VIE based on a number of factors, including (i) which party has the power to direct the activities that most significantly affect the VIE’s economic performance, (ii) the parties’ contractual rights and responsibilities pursuant to any contractual agreements and (iii) which party has the obligation to absorb losses or the right to receive benefits from the VIE. If the Company determines that it is the primary beneficiary of a VIE, it consolidates the financial statements of the VIE into its consolidated financial statements at the time that determination is made. On a quarterly basis, the Company evaluates whether it continues to be the primary beneficiary of any consolidated VIEs. If the Company determines that it is no longer the primary beneficiary of a consolidated VIE, or no longer has a variable interest in the VIE, the Company deconsolidates the VIE in the period that the determination is made. Investment The Company accounts for investments in equity securities without a readily determinable fair value at cost, minus impairment. If the Company identifies observable price changes in orderly transactions for an identical or a similar investment of the same issuer, the Company will measure the equity security at fair value as of the date that the observable transaction occurred in accordance with ASC Topic 321, Investments-Equity Securities. Use of Estimates The preparation of consolidated financial statements in accordance with U.S. generally accepted accounting principles ("GAAP") requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of expenses during the reported periods. On an ongoing basis, the Company’s management evaluates its estimates, judgments and methodologies. Significant estimates and assumptions in the consolidated financial statements include those related to revenue, fair value determination of other investment, income taxes, including the valuation allowance for deferred tax assets, research and development expenses, contingencies, share-based compensation and going concern. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known. Cash and Cash Equivalents The Company considers all highly liquid investment instruments with a remaining maturity when purchased of three months or less to be cash equivalents. Investments qualifying as cash equivalents may consist of F- 11 money market funds and overnight repurchase agreements. The carrying amount of cash equivalents approximates fair value. Fair Value of Investment Instruments Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. Foreign Currency Translation Adjustment The functional currency of the Company’s former foreign subsidiary is its local currency, the Swiss franc. The assets and liabilities of the Company’s former foreign subsidiary are translated into U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense items are translated at the average exchange rates prevailing during the period. The cumulative translation effect for the Company’s former foreign subsidiary was included as a foreign currency translation adjustment in the consolidated statements of stockholders’ equity and as a component of comprehensive loss in the consolidated statements of operations and comprehensive loss. The Company’s intercompany accounts are typically denominated in the functional currency of the foreign subsidiary. Gains and losses resulting from the re-measurement of intercompany balances are recorded in the consolidated statements of operations. Accounts Receivable The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for receivables when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices. The Company believes that credit risks associated with these agreements are not significant. To date, the Company has not had significant write-offs of bad debt and the Company did not have an allowance for doubtful accounts as of December 31, 2025 or 2024 . Revenue Upon executing a revenue generating arrangement, the Company assesses whether it is probable the Company will collect consideration in exchange for the good or service it transfers to the customer. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”), it performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies the performance obligations. The Company must develop assumptions that require significant judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The assumptions that are used to determine the stand-alone selling price may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory F- 12 success. The Company derives revenue from (1) license agreement, (2) purchase agreement and (3) option to license agreement which are fully described in Note 11, License and Option Agreement . Research and Development Costs The Company expenses research and development costs to operations as incurred. The Company defers and capitalizes nonrefundable advance payments made by the Company for research and development activities until the related goods are received or the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company will adjust the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception. Research and development expenses are comprised of costs incurred in performing research and development activities, which may include salary, benefits and other employee-related expenses; share-based compensation expense; laboratory supplies and other direct expenses; facilities expenses; overhead expenses; third-party contractual costs relating to nonclinical studies and clinical trial activities and related contract manufacturing expenses, development of manufacturing processes and regulatory registration of third-party manufacturing facilities; and other outside expenses. General and Administrative Expenses The Company expenses general and administrative costs to operations as incurred. General and administrative expense consists of compensation, share-based compensation, benefits and other employee-related expenses for personnel and outside consultants providing the Company’s administrative, finance, legal, information technology, business development and human resource functions. Other costs include the legal costs of pursuing patent protection of the Company’s intellectual property, general and administrative related facility costs, insurance costs and professional fees for accounting and legal services. Income taxes The Company is primarily subject to U.S. Federal and Massachusetts state income taxes. For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, the Company provides a valuation allowance, if necessary, to reduce deferred tax assets to amounts that are realizable. The tax positions taken or expected to be taken in the course of preparing the Company tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold would be recorded as a tax expense in the current year. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. It does not consider the likelihood of whether or not the IRS will review the position. Cyclerion evaluates uncertain tax positions on a quarterly basis and adjusts the level of the liability to reflect any subsequent changes in the relevant facts surrounding the uncertain positions. Any changes to these estimates, based on the actual results obtained and/or a change in assumptions, could affect Cyclerion's income tax provision in future periods. There were no uncertain tax positions that require accrual or disclosure in the consolidated financial statements as of December 31, 2025, and 2024. The Company’s policy is to recognize interest and penalties related to income tax, if any, in income tax expense. As of December 31, 2025 and 2024 , the Company has no accruals for interest or penalties related to income tax matters. F- 13 Patent Costs Patent fees and patent related costs in connection with filing and prosecuting patent applications are expensed as incurred and are classified as general and administrative expenses in the accompanying consolidated financial statements. The Company incurred and recorded as operating expense legal and other fees related to patents of approximately $ 0.3 million and $ 0.6 million for the years ended December 31, 2025 and 2024 , respectively. Interest and Other Income, Net For the year ended December 31, 2025 and 2024, interest and other income, net consisted of a $ 0.1 million and $ 0.2 million of interest income related to interest generated from the Company's cash and cash equivalents balances, respectively. Subsequent Events The Company considers events or transactions that have occurred after the balance sheet date of December 31, 2025, but prior to the filing of the financial statements with the Securities and Exchange Commission, to provide additional evidence relative to certain estimates or to identify matters that require additional recognition or disclosure. Subsequent events have been evaluated through the filing of the financial statements accompanying this Annual Report on Form 10-K. See Note 12, Subsequent Events . Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as discussed elsewhere in the notes to the consolidated financial statements, the Company did not adopt any new accounting pronouncements during the years ended December 31, 2025 and 2024, that had a material effect on its consolidated financial statements. In August 2025, the FASB issued ASU No. 2025-05, Financial Instruments—Credit Losses (Topic 326), which requires incremental disclosures on estimating expected credit losses. The Company will adopt this guidance beginning with its annual report for fiscal 2027. The Company is currently evaluating the potential effect that the updated standard will have on its financial statement disclosures. Recently Adopted Accounting Pronouncements In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures (Topic 280), which requires incremental disclosures on reportable segments, primarily through enhanced disclosures on significant segment expenses. The Company adopted this guidance beginning with its annual report for fiscal 2025 and interim periods thereafter on a retrospective basis. The adoption did not have a material effect on the consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which focuses on the rate reconciliation and income taxes paid. ASU No. 2023-09 requires a public business entity (PBE) 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. For PBEs, the new standard is effective for annual periods beginning after December 15, 2024, with early adoption permitted. For entities other than PBEs, the requirements will be effective for annual periods beginning after December 15, 2025. An entity may apply the amendments in this ASU prospectively by providing the revised disclosures for the period ending December 31, 2025 and continuing to provide the pre-ASU disclosures for the prior periods, or may apply the amendments retrospectively by providing the revised disclosures for all period presented. As of December 31, F- 14 2025, the Company adopted this new ASU and it only impacts the Company's income tax disclosures with no impact to its operations, cash flows, or financial condition. No other accounting standards known by the Company to be applicable to it that have been issued by the FASB or other standard-setting bodies and that do not require adoption until a future date are expected to have a material impact on the Company’s consolidated financial statements upon adoption. 3. Fair Value of Financial Instruments The Company’s cash equivalents are generally classified within Level 1 of the fair value hierarchy. The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values as of December 31, 2025 and December 31, 2024 (in thousands): Fair Value Measurements as of December 31, 2025: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 3,072 $ — $ — $ 3,072 Cash equivalents $ 3,072 $ — $ — $ 3,072 Fair Value Measurements as of December 31, 2024: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 3,025 $ — $ — $ 3,025 Cash equivalents $ 3,025 $ — $ — $ 3,025 During the year ended December 31, 2025 and 2024, there were no transfers between levels. The fair value of the Company's cash equivalents, consisting of money market funds, is based on quoted market prices in active markets with no valuation adjustment. The Company believes the carrying amounts of its accounts receivable, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these amounts. 4. Other Investment On July 28, 2023, the Company closed the transactions contemplated by the Asset Purchase Agreement receiving proceeds of $ 8.0 million as cash consideration, approximately $ 2.4 million as reimbursement for certain operating expenses related to zagociguat and CY3018 programs for the period between signing and closing of the transaction, and 10 % of all of Tisento Parent's outstanding equity securities which fair value was determined to be $ 5.3 million at the time of closing. The Company’s investment in Tisento Parent does not provide it with significant influence over Tisento Parent. The Company has determined that the Company’s investment in Tisento Parent is an equity security, whereby such investment does not give the Company a controlling financial interest or significant influence over the investee. Further, the Company assessed the accounting for its investment in Tisento Parent in accordance with ASC 810-10, Consolidation—Overall. After determining that no scope exception applies under the guidance of ASC 810-10-15-12 and ASC 810-10-15-17, the Company concluded that it has a variable interest in Tisento Parent through its investment in Tisento Parent common stock. Tisento Parent does not have sufficient equity to finance its activities without additional subordinated financial support as Tisento Parent is a startup entity in its early stages of raising funds and will require significant capital to advance its programs to commercial stage. Therefore, the Company concluded that its investment in Tisento Parent is a variable interest entity (“VIE”) in accordance with ASC 810-10-15-14(a) and is subject to potential consolidation under the VIE model. However, all activities that most significantly impact Tisento Parent and its subsidiary’s economic performance are directed by the Tisento Parent board and the board approves decisions by a simple majority. Based on the board composition, the Company F- 15 determined that no one party has control over the Tisento Parent board and power is not shared because the activities that most significantly affect Tisento Parent and its subsidiary’s economic performance do not require the consent of all of the parties. Rather, all decisions are made by a simple majority vote of the Tisento Parent board. Therefore, because the Company controls no director of Tisento Parent, the Company cannot unilaterally direct any of the activities that most significantly impact Tisento Parent and its subsidiary’s economic performance. Accordingly, the Company does not hold a controlling financial interest in Tisento Parent. Because both criteria (a) and (b) above have to be met for the application of the guidance in ASC 810-10-25-44B and criteria (a) has not been met, The Company concluded that it should not consolidate Tisento under the VIE model. Accordingly, the Company has accounted for the investment as a financial instrument without a readily determinable fair value. Such investment is recorded using the measurement alternative for investments without readily determinable fair values, whereby the investment is measured at cost less any impairment recorded or adjustments for observable price changes. An impairment loss is recognized in the consolidated statements of operations and comprehensive loss equal to the amount by which the carrying value exceeds the fair value of the investment. As of December 31, 2025 , no impairment loss was recognized. The Company considers the cost of the investment to be the maximum exposure to loss as a result of its involvement with the non-affiliated entity. The initial fair value of the investment in Tisento Parent was determined by reference to the risk-adjusted net assets value using the discounted cash flow method. The estimated net assets value of Tisento Parent includes the cash generated/used from the operations and the proceeds from equity financing. Valuations were derived by reference to observable valuation measures for comparable companies or transactions, including weighted average cost of capital ( 21 % to 23 %), terminal decline rate ( 25 % to 75 %) and the discount rate referenced by a two-year treasury rate of 4.01 %. 5. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): December 31, December 31, 2025 2024 Professional fees $ 143 $ 220 Employee compensation 13 33 Other 38 30 Accrued expenses and other current liabilities $ 194 $ 283 6. Commitments and Contingencies Other Funding Commitments The Company may enter into contracts with clinical research organizations and other third parties for clinical and preclinical research studies and other services and products for operating purposes. These contracts are generally cancellable, with notice, at the Company’s option and do not have any significant cancellation penalties. Guarantees On September 6, 2018, Cyclerion was incorporated in Massachusetts and its officers and directors are indemnified for certain events or occurrences while they are serving in such capacity. The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with directors and officers, business partners, contractors, clinical sites and customers. Under these provisions, the Company generally indemnifies and holds harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of the Company’s activities. These indemnification provisions generally survive termination of the underlying agreements. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date the Company has not incurred material costs to defend F- 16 lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal. Accordingly, the Company did no t have any liabilities recorded for these obligations as of December 31, 2025 or December 31, 2024. Separation Benefits As part of the separation benefit of the former Chief Financial Officer, the Company paid $ 0.1 million each in May 2024 and August 2024. The Company has no further separation benefits obligation as of December 31, 2025 and 2024. 7. Share-based Compensation Plans In 2019, Cyclerion adopted share-based compensation plans. Specifically, Cyclerion adopted the 2019 Employee Stock Purchase Plan (“2019 ESPP”) and the 2019 Equity Incentive Plan (“2019 Equity Plan”). Under the 2019 ESPP, eligible employees may use payroll deductions to purchase shares of stock in offerings under the plan, and thereby acquire an interest in the future of the Company. The 2019 Equity Plan provides for stock options, restricted stock awards ("RSAs") and restricted stock units (“RSUs”). Cyclerion also mirrored two of Ironwood Pharmaceuticals, Inc. ("Ironwood") existing plans, the Amended and Restated 2005 Stock Incentive Plan (“2005 Equity Plan”) and the Amended and Restated 2010 Employee, Director and Consultant Equity Incentive Plan (“2010 Equity Plan"). These mirror plans were adopted to facilitate the exchange of Ironwood equity awards for Cyclerion equity awards upon the Separation as part of the equity conversion. As a result of the Separation and in accordance with the EMA, employees of both companies retained their existing Ironwood vested options and received a pro-rata share of Cyclerion options, regardless of which company employed them post-Separation. For employees that were ultimately employed by Cyclerion, unvested Ironwood options and RSUs were converted to unvested Cyclerion options and RSUs. The following table provides share-based compensation reflected in the Company’s consolidated statements of operations and comprehensive loss for the years ended December 31, 2025 and 2024 (in thousands): Year Ended December 31, 2025 2024 Research and development $ 29 $ 91 General and administrative 412 534 $ 441 $ 625 Stock Options Stock options granted under the Company’s equity plans generally have a ten-year term and vest over a period of four years, provided the individual continues to serve at the Company through the vesting dates. Options granted under all equity plans are exercisable at a price per share not less than the fair market value of the underlying common stock on the date of grant. The estimated fair value of options, including the effect of estimated forfeitures, is recognized over the requisite service period, which is typically the vesting period of each option. A summary of stock option activity for the year ended December 31, 2025 is as follows: F- 17 Weighted Weighted Average Average Average Remaining Intrinsic Number Exercise Contractual Value (in of Options Price Term (Years) thousands) Outstanding as of December 31, 2024 335,448 $ 158.98 4.7 $ — Granted 25,000 $ 2.36 Exercised — $ — Cancelled or forfeited ( 62,686 ) $ 140.44 Outstanding as of December 31, 2025 297,762 $ 149.73 4.9 $ — Exercisable at December 31, 2025 232,385 $ 187.20 4.0 $ — During the years ended December 31, 2025 and 2024, the Company granted stock options to purchase an aggregate of 25,000 shares and 55,849 shares, respectively, at weighted average grant date fair values per option share of $ 2.14 and $ 2.80 respectively. There were no options exercised during the year ended December 31, 2025 and 2024. As of December 31, 2025, the unrecognized share-based compensation expense, net of estimated forfeitures, related to all unvested time-based stock options held by the Company’s employee and non-employees is $ 0.1 million and the weighted average period over which that expense is expected to be recognized is 3.03 years. The weighted-average Black-Scholes assumptions used in estimating the fair value of the stock options granted by Cyclerion during the years ended December 31, 2025 and 2024 were as follows: Year ended December 31, 2025 2024 Weighted average risk-free interest rate 3.79 % 3.64 % Expected dividend yield — — Expected option term (in years) 5.4 6.0 Expected stock price volatility 141.07 % 111.97 % For the years ended December 31, 2025 and 2024, expected volatility was estimated using an average of the historical volatility of the common stock of a group of similar companies that were publicly traded. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. The Company has granted certain employees performance-based options to purchase shares of common stock. These options are subject to performance-based milestone vesting. During the year ended December 31, 2025 and 2024, there were no shares that vested as a result of performance milestone achievements. No share-based compensation expense related to these performance-based options was recognized during the years ended December 31, 2025, and 2024, respectively. Restricted Stock Awards No RSA was granted during the year ended December 31, 2025. The Company granted 65,000 RSAs during the year ended December 31, 2024. The fair value of all RSAs is based on the market value of the Company’s common stock on the date of grant. Compensation expense, including the effect of estimated forfeitures, is recognized over the applicable service period. F- 18 A summary of RSA activity for the years ended December 31, 2025 is as follows: Weighted Average Number Grant Date of Shares Fair Value Unvested as of December 31, 2024 164,174 $ 2.56 Granted — — Vested ( 60,096 ) 2.52 Forfeited — — Unvested as of December 31, 2025 104,078 $ 2.57 As of December 31, 2025, the unrecognized share-based compensation expense, net of estimated forfeitures, related to all unvested RSAs held by the Company’s directors is $ 0.2 million and the weighted average period over which that expense is expected to be recognized is 1.69 years. 8 . Loss per share Basic and diluted net loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding during the period as follows: Year Ended December 31, 2025 2024 Numerator: Net loss (in thousands) $ ( 3,528 ) $ ( 3,057 ) Denominator: Weighted average shares used in calculating net loss per share — basic and diluted (in thousands) 3,181 2,518 Net loss per share — basic and diluted $ ( 1.11 ) $ ( 1.21 ) The Company excludes potential shares of common stock related to Preferred Stock, stock options and RSAs from the calculation of diluted net loss per share since the inclusion of such shares would be anti-dilutive. The following table sets forth potential shares that were considered anti-dilutive for the years ended December 31, 2025 and 2024: Yer Ended December 31, 2025 2024 Preferred Stock 351,037 351,037 Stock Options 297,762 335,448 RSAs 104,078 164,174 752,877 850,659 9. Income Taxes The components of net income (loss) before income tax expense are as follows (in thousands): F- 19 Year Ended December 31, 2025 2024 Domestic $ ( 3,528 ) $ ( 3,061 ) Foreign — 3 Total $ ( 3,528 ) $ ( 3,058 ) A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows after adoption of ASU 2023-09 on a retrospective basis (in thousands): Year Ended December 31, 2025 2024 Amount Percent Amount Percent Pretax loss $ ( 3,528 ) $ ( 3,058 ) US Federal Statutory Tax Rate ( 741 ) 21.0 % ( 642 ) 21.0 % Foreign tax effects — — ( 1 ) 0.0 % Non-deductible items 571 - 16.2 % 88 - 2.9 % Tax credits — — ( 11 ) 0.4 % Change in valuation allowance 170 - 4.8 % 566 - 18.5 % $ — 0.0 % $ — 0.0 % The Company’s effective tax rate differs from the statutory rate primarily due to continued losses and the maintenance of a full valuation allowance on deferred tax assets, resulting in zero income tax expense for the period. Deferred tax assets (liabilities) consist of the following as of December 31, 2025 and 2024 (in thousands): Year Ended December 31, 2025 2024 Deferred tax assets: Net operating loss carryforwards $ 57,618 $ 53,281 Tax credit carryforwards 10,385 10,383 Share-based compensation 6,500 7,122 Capitalized research and development 8,867 12,370 Intangibles 20 — Total deferred tax assets $ 83,390 $ 83,156 Valuation allowance ( 83,390 ) ( 83,156 ) Net deferred tax assets $ — $ — The Company has evaluated the positive and negative evidence bearing upon the possible realization of its deferred tax assets. Management has considered the Company's history of operating losses, in addition to the expected timing of the reversal of existing temporary differences and concluded, in accordance with the applicable accounting standards, that it is more likely than not that the Company will not realize the benefit of its deferred tax assets. Accordingly, the net deferred tax assets have been fully reserved at December 31, 2025 and December 31, 2024. Management reevaluates the positive and negative evidence on a quarterly basis. The valuation allowance increased by approximately $ 0.2 million during the year ended December 31, 2025 primarily due to increases in capitalized research and development expenses, net operating losses, tax credit carryforwards and deferred tax assets related to share-based compensation. At December 31, 2025 and 2024 , Cyclerion has federal net operating loss carryforwards of approximately $ 211 million and $ 195 million, respectively, to offset future federal taxable income that will be carried forward indefinitely until utilized. As of December 31, 2025 and 2024 , Cyclerion had state net operating loss carryforwards of approximately $ 212 million and $ 196 million, respectively, to offset future state taxable income, which will begin F- 20 to expire in 2039 and will continue to expire through 2045 . Cyclerion also had tax credit carryforwards of approximately $ 10.8 million as of December 31, 2025 , to offset future federal and state income taxes. Federal credits begin to expire in 2039 and will continue to expire through 2044. State credits begin to expire in 2034 and continue through 2039 . The Company’s ability to use its operating loss carryforwards and tax credits to offset future taxable income could be subject to restrictions under Section 382 of the U.S. Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). These potential restrictions may limit the future use of the operating loss carryforwards and tax credits if certain ownership changes described in the Internal Revenue Code occur. Changes in stock ownership may occur that would create these limitations on the Company’s use of the operating loss carryforwards and tax credits. In such a situation, the Company may be required to pay income taxes, even though significant operating loss carryforwards and tax credits exist. The Company has not as yet conducted a study of its research and development credit carry forwards. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s research and development credits, and if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the consolidated balance sheets or statements of operations if an adjustment were required. Upon audit, taxing authorities may challenge all or part of an uncertain income tax position. While Cyclerion has no history of tax audits since its inception on a standalone basis, it may be subject to tax audits by federal and state taxing authorities in the future. Accordingly, Cyclerion regularly assesses the outcome of potential examinations in each of the taxing jurisdictions when determining the adequacy of the amount of unrecognized tax benefit recorded. Cyclerion had no unrecognized tax benefits as of December 31, 2025 and 2024. Cyclerion will recognize interest and penalties, if any, related to uncertain tax positions in income tax expense. As of December 31, 2025 and 2024 , no interest or penalties have been accrued. There are no current federal or state income tax audits in progress. 10. Defined Contribution Plan The Company has established a defined contribution 401(k) Savings Plan which allows eligible employees to contribute from 1 % to 100 % of their compensation, subject to certain IRS limits. The Company's contributions to the plan are at the sole discretion of the board of directors. Currently, the Company provides a matching contribution of 75 % of the employee’s contributions, up to $ 6,000 annually. Included in compensation expense is de minimis related to the defined contribution 401(k) Savings Plan for the years ended December 31, 2025 and 2024 , respectively. 11. License and Option Agreement Patent License Agreement On September 19, 2025, the Company and MIT entered into a Patent License Agreement (the “MIT License Agreement”) pursuant to which MIT granted to the Company an exclusive worldwide license to develop and commercialize products using certain technology for the treatment of neuropsychiatric disorders, such as depression, in humans. Under the MIT License Agreement, the Company paid a nominal upfront license fee and patent reimbursement fee. Thereafter, the Company is also required to pay MIT a nominal annual license maintenance fee. This annual license maintenance fee is nonrefundable; however, the license maintenance fee may be credited to royalties earned during the same calendar year, if any. License maintenance fees paid in excess of royalties due in such calendar year shall not be creditable to amounts due for future years. Under the terms of the MIT License Agreement, MIT will be eligible to receive up to $ 4.4 million upon the achievement of certain development, regulatory and sales milestone payments. MIT will also receive tiered royalties in a range of percentages in the low single digits based on future net sales of licensed products as set forth in the MIT License Agreement. Further, the Company is required to pay MIT varying percentages of income received as consideration for any sublicenses granted pursuant to the MIT License Agreement depending on the circumstances of the F- 21 sublicense and the development milestones of sublicensed products. The term of the MIT License Agreement will expire in its entirety upon the expiration of certain patent rights for the licensed patents, unless earlier terminated by the parties in accordance with the terms of the MIT License Agreement. The Company recorded research and development expense of $ 0.1 million for the year ended December 31, 2025, which consisted of upfront fees, patent reimbursement fees and transaction costs related to the license. Akebia License Agreement On June 3, 2021, the Company and Akebia entered into a License Agreement (the “Akebia License Agreement”) relating to the exclusive worldwide license by the Company to Akebia of its rights to the development, manufacture, medical affairs and commercialization of pharmaceutical products containing the pharmaceutical compound known as praliciguat and other related products and forms thereof enumerated in the License Agreement (collectively, the “Products”). Pursuant to the Akebia License Agreement, Akebia will be responsible for all future research, development, regulatory, and commercialization activities for the Products. Akebia paid a $ 3.0 million up-front payment to the Company upon signing of the License Agreement. On December 13, 2024, the Company and Akebia entered into Amendment #1 to the License Agreement (the “2024 Amendment”) to the original License Agreement between the parties dated June 3, 2021. Under the terms of the 2024 Amendment, Akebia paid $ 1.75 million in amendment payments, of which $ 1.25 million was paid in December 2024 and an additional payment of $ 0.5 million was paid in September 2025. In addition, Akebia has agreed to assume control of the preparation, filing, prosecution and maintenance of certain Cyclerion patents, and the expenses associated therewith, at an earlier date than as originally agreed between the parties. The parties have agreed to the reduction of certain development milestones and the increase of certain royalty rates on net sales and sublicense income. On December 1, 2025, Akebia publicly announced that it has recently initiated Phase 2 clinical trials for the treatment of focal segmental glomerulosclerosis (“FSGS”) using praliciguat. Pursuant to the terms of amendment, upon initiation of a Phase 2 clinical trial in the U.S. for a product, a $ 1.0 million development milestone payment would be due to the Company and which was received in February 2026. Pursuant to the terms of the Akebia License Agreement, as amended, Cyclerion is eligible to receive additional potential future development, regulatory, and commercialization milestone payments up to $ 557.5 million i n total, and Akebia will pay Cyclerion tiered royalties ranging from mid-single digit to twenty percent of net sales. Cyclerion’s obligations to deliver certain drug products have also ceased. Pursuant to the Akebia License Agreement, the Company determined the Akebia License Agreement represents a service arrangement under the scope of ASC 606. Given the reversion of the rights under the Akebia License Agreement represents a penalty in substance for a termination by Akebia, the contract term would be the stated term of the License Agreement. The Company determined that the grant of license to its patents and trademarks, know how transfer, the assignment of regulatory submissions and trademarks and additional knowledge transfer assistance obligations represent a single promise and performance obligation to be transferred to Akebia over time due to the nature of the promises in the contract. The provision of development materials on hand was identified as a separate performance obligation. However, it is immaterial in the context of the contract as the development materials are low value and do not have an alternative use to the Company. The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur as these amounts have been determined to relate predominantly to the license. The Company will re-evaluate the probability of achievement of the milestones and any related constraints each reporting period. Akebia Material Purchase Agreement On September 3, 2025, the Company and Akebia entered into a Material Purchase Agreement (the “Purchase Agreement”) relating to the purchase of additional development materials (the "Additional Development Materials") by Akebia for Akebia's use pursuant to the Akebia License Agreement. Akebia paid $ 0.8 million to the Company for the purchase during the year ended December 31, 2025 and the Additional Development Materials F- 22 were delivered to Akebia as of December 31, 2025. The Company determined the Purchase Agreement has stand-alone value under the scope of ASC 606 and should not be combined with the Akebia License Agreement or the Amendment. The delivery of the Additional Development Materials by the Company represents a single performance obligation and consideration was recognized upon delivery. The Company recognized revenue of $ 0.8 million during the year ended December 31, 2025. Option Agreement On July 22, 2024, the Company entered into an Option to License Agreement (the “Option Agreement”) with a third party (the “Optionee”), pursuant to which the Optionee had an option (the “Option”) to enter into an exclusive license to olinciguat for human therapeutics, subject to certain carveouts. Under the terms of the Option Agreement, the Optionee paid the Company an Option fee of $ 150,000 in August 2024 and subsequent fees totaling $ 80,000 to extend the term of the Option Agreement. The Optionee originally could exercise the Option on or before March 20, 2025, which option period was ultimately extended through August 22, 2025. Thereafter, the parties had an additional 60 days to negotiate the terms of a definitive license agreement. The parties were unable to agree upon the terms of a license agreement and the Company provided notice on October 23, 2025 that it was terminating the Option Agreement. 12. Subseq uent Events On January 6, 2026, the Company sold 405,000 shares of common stock under the Sales Agreement for net proceeds of approximately $ 0.8 million . The Company exhausted all sales under the 2025 Shelf. On January 3, 2026, the Company and the Medsteer, SAS (“Medsteer”) entered into a Collaboration and Option Agreement (the “Collaboration Agreement”) pursuant to which Medsteer granted to the Company (i) a non-exclusive, worldwide, royalty-free, sublicensable license of certain of Medsteer’s technology, software and intellectual property to develop an anesthetic delivery system with Medsteer and (ii) an exclusive option (the “Option”), exercisable at the Company’s sole discretion, to obtain an exclusive, worldwide, royalty-bearing, sublicensable license of certain of Medsteer’s technology, software and intellectual property to develop or commercialize licensed products in any field of use except for sedation regulation for patients undergoing major surgery, in multi-bed or intensive unit wards, or in the context of medical transport. The Company may exercise the Option at any time until the earlier of the second anniversary of the effective date of the Collaboration Agreement, which period may be extended for an addition two years at the Company’s option and upon payment of a nominal fee or by mutual agreement of the Company and Medsteer. Under the terms of the Collaboration Agreement, the Company will pay to Medsteer a nominal upfront payment, a payment upon exercise of the Option, and Medsteer will be eligible to receive up to $ 3.7 million upon the achievement of certain development, regulatory and sales milestone payments. Medsteer will also receive an annual royalty payment and royalties in a percentage in the low single digits based on future net sales of licensed products, subject to certain adjustments as set forth in the Collaboration Agreement. F- 23