Terrance McGuire - 30 Nov 2023 Form 4 Insider Report for Cyclerion Therapeutics, Inc. (CYCN)

Footnote F1

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.

Footnote F2

The reportable securities are owned directly by Polaris Partners VIII, L.P. ("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.

Footnote F3

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 PPGPVIII. 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.

Footnote F4

The Reporting Person is a managing member of Bartlett Partners, LLC, the beneficial owner of the securities. The Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that he is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of his pecuniary interest therein.