CYCN

The Reporting Person was granted an option to purchase up to 25,000 shares of the Corporation's common stock pursuant to the 2019 Equity Incentive Plan. These 25,000 shares vest as follows: (i) 8,750 shares are immediately exercisable, and (ii) the remaining 16,250 shares vest ratably in monthly installments commencing August 31, 2025 and ending on February 28, 2028, provided that the Reporting Person remains as a consultant or employee of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

On March 25, 2025, the reporting person purchased directly from the Issuer 9,090 shares of Common Stock for a total purchase price of approximately $25,000 (or $2.75 per share) in a private placement transaction pursuant to the Stock Purchase Agreement dated as of March 21, 2025 by and among the Issuer and the investors named therein.

On March 25, 2025, the reporting person purchased directly from the Issuer 181,818 shares of Common Stock for a total purchase price of approximately $500,000 (or $2.75 per share) in a private placement transaction pursuant to the Stock Purchase Agreement dated as of March 21, 2025 by and among the Issuer and the investors named therein.

The number of shares reported herein reflect the one-for-twenty reverse stock split effected by the Issuer on May 15, 2023.

The securities to which this filing relates were held by certain funds (the "Slate Path Funds"). Slate Path Capital LP (the "Investment Manager"), a Delaware limited partnership acts as the investment manager of the Slate Path Funds. Mr. David Greenspan serves as the managing member of Jades GP, LLC, a Delaware limited liability company and the general partner of the Investment Manager. The filing of this statement shall not be deemed an admission that either Reporting Person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Act of 1934, as amended, or otherwise. Each of the Reporting Persons expressly disclaims beneficial ownership of the securities reported herein except to the extent of its pecuniary interest therein, if any.

The Reporting Person was granted an option to purchase up to 55,849 shares of the Corporation's common stock pursuant to the 2019 Equity Incentive Plan. These 55,849 shares vest ratably in monthly installments over a 48-month period commencing August 31, 2024 and ending July 31, 2028, provided that the Reporting Person remains employed by Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 50,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 10,000 of the shares vest immediately and the remaining 40,000 shares are subject to vesting ratably over a 48-month period, provided that the Reporting Person remains employed by Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 15,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. These 15,000 shares are subject to vesting over a 47- month period, provided that the Reporting Person remains a consultant to the Cyclerion Therapeutics or a member of the board of directors of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 15,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. These 15,000 shares are subject to vesting over a 48- month period, provided that the Reporting Person remains a consultant to the Cyclerion Therapeutics or a member of the board of directors of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 30,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 3,750 of these shares vest immediately and the remaining 26,250 shares vest ratably over a 42-month period, provided that the Reporting Person remains as Chair of the Board of Directors of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 20,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 2,500 of the shares vest immediately and the remaining 17,500 shares are subject to vesting ratably over a 42-month period, provided that the Reporting Person remains as a director of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 20,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 2,500 of the shares vest immediately and the remaining 17,500 shares are subject to vesting ratably over a 42-month period, provided that the Reporting Person remains as a director of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 20,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 2,500 of these shares vest immediately and the remaining 17,500 shares vest ratably over a 42-month period, provided that the Reporting Person remains as a director of Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

The Reporting Person was granted 5,000 shares of restricted stock pursuant to the Cyclerion Therapeutics, Inc. 2019 Equity Incentive Plan. 2,500 of these shares vest immediately and the remaining 2,500 of these shares vest over the next 6 months, provided that the Reporting Person remains as a director of Cylerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions.

On May 15, 2023, the Issuer effected a 1-for-20 reverse stock split of all of its shares of Common Stock resulting in a corresponding reduction of the Reporting Person's direct and indirect ownership of Common Stock.

The Reporting Person and Jonathan Flint ("Flint") are the managing members of Polaris Venture Management Co. II, L.L.C., the beneficial owner of the securities. Each of the Reporting Person and Flint disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

On May 19, 2023, the reporting person purchased directly from the Issuer 225,000 shares of Common Stock and 351,037 shares of Series A Convertible Preferred Stock (the "Series A Preferred Stock") for a total purchase price of approximately $5,000,000 (or $8.68 per share) in a private placement transaction pursuant to the Stock Purchase Agreement dated as of March 31, 2023 between the reporting person and the Issuer. The Series A Preferred Stock may be converted to Common Stock on a one-for-one basis at the option of the holder thereof. The reporting person has agreed not to convert his Series A Preferred Stock to the extent such conversion would require shareholder approval pursuant to Nasdaq listing rules and such shareholder approval has not been obtained.

On May 19, 2023, the reporting person purchased directly from the Issuer 225,000 shares of Common Stock and 351,037 shares of Series A Convertible Preferred Stock (the "Series A Preferred Stock") for a total purchase price of approximately $5,000,000 (or $8.68 per share) in a private placement transaction pursuant to the Stock Purchase Agreement dated as of March 31, 2023 between the reporting person and the Issuer. The Series A Preferred Stock may be converted to Common Stock on a one-for-one basis at the option of the holder thereof. The reporting person has agreed not to convert his Series A Preferred Stock to the extent such conversion would require shareholder approval pursuant to Nasdaq listing rules and such shareholder approval has not been obtained.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options were granted pursuant to the director compensation plan. 17,753 options will vest in full on the first anniversary of the grant date and 40,000 options will vest monthly pro rata over 36 months starting on the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 20, 2022.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 20, 2022.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 20, 2022.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 20, 2022.

The stock option vests and becomes exercisable as to 8.33333% of the shares of Common Stock on each monthly anniversary of January 3, 2022.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of December 9, 2021.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of December 9, 2021.

The stock option vests and becomes exercisable as to 2.08333% of the shares of Common Stock on each monthly anniversary of December 9, 2021.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

. The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

The options, granted pursuant to the director compensation plan, will vest in full on the first anniversary of the grant date.

On June 3, 2021, Polaris Partners VIII, L.P. ("PP VIII") and Polaris Entrepreneurs' Fund VIII, L.P. ("PEF VIII") agreed to purchase directly from the Issuer such shares of Common Stock of the Issuer in a private placement transaction.

The reportable securities are owned directly by PP VIII. Polaris Partners GP VIII, L.L.C. ("PPGP VIII") is the general partner of PP VIII. The Reporting Person, a member of the Issuer's Board of Directors, is an interest holder of PPGP VIII. Each of David Barrett, Brian Chee, Amir Nashat and Bryce Youngren are the managing members of PPGP VIII (collectively, the "Managing Members"). Each of the Reporting Person and the Managing Members, in their respective capacities with respect to PPGP VIII, may be deemed to have shared voting and dispositive power over the shares held by PP VIII. Each of PPGP VIII, the Reporting Person and the Managing Members disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

On June 3, 2021, the reporting person agreed to purchase directly from the Issuer 823,170 shares of Common Stock of the Issuer in a private placement transaction.

On June 3, 2021, Polaris Partners VIII, L.P. ("PP VIII") and Polaris Entrepreneurs' Fund VIII, L.P. ("PEF VIII") agreed to purchase directly from the Issuer such shares of Common Stock of the Issuer in a private placement transaction.

The reportable securities are owned directly by PEF VIII. PPGP VIII is the general partner of PEF VIII. The Reporting Person, a member of the Issuer's Board of Directors, is an interest holder of PPGP VIII. Each of the Reporting Person and the Managing Members, in their respective capacities with respect to PPGP VIII, may be deemed to have shared voting and dispositive power over the shares held by PEF VIII. Each of PPGP VIII, the Reporting Person and the Managing Members disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

The securities to which this filing relates are held by Slate Path Master Fund LP (the "Master Fund"), a Cayman Islands exempted limited partnership. Slate Path Capital LP (the "Investment Manager"), a Delaware limited partnership acts as the investment manager of the Master Fund. Mr. David Greenspan serves as the managing member of Jades GP, LLC, a Delaware limited liability company and the general partner of the Investment Manager. The filing of this statement shall not be deemed an admission that either Reporting Person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Act of 1934, as amended, or otherwise. Each of the Reporting Persons expressly disclaims beneficial ownership of the securities reported herein except to the extent of its pecuniary interest therein.

The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.31 to $2.59, inclusive. The reporting person will provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each price within the range set forth in this footnote.

The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.32 to $2.61, inclusive. The reporting person will provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each price within the range set forth in this footnote.

The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.10 to $2.45, inclusive. The reporting person will provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each price within the range set forth in this footnote.

This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. This sale was made to cover tax withholding obligations in connection with the vesting and settlement of approximately 25% of the reporting person's restricted stock units granted on April 1, 2019.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.80 to $4.00, inclusive. The reporting person will provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the range set forth in this footnote.

This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. This sale was made to cover tax withholding obligations in connection with the vesting and settlement of approximately 25% of the reporting person's restricted stock units granted on April 1, 2019.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.80 to $4.00, inclusive. The reporting person will provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the range set forth in this footnote.