Cyclerion Therapeutics, Inc. New Standards Disclosure

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,

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.