X0306 4 2019-04-01 0 0001755237 Cyclerion Therapeutics, Inc. CYCN 0001478244 Currie Mark G C/O CYCLERION THERAPEUTICS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 0 1 0 0 President Common Stock 2019-04-01 4 A 0 51648 0.00 A 51648 D Common Stock 2019-04-02 4 P 0 270107 14.81 A 321755 D Employee Stock Option (Right to Buy) 12.39 2019-04-01 4 A 0 888 0.00 A 2020-02-02 Common Stock 888 888 D Employee Stock Option (Right to Buy) 12.23 2019-04-01 4 A 0 37286 0.00 A 2021-02-01 Common Stock 37286 37286 D Employee Stock Option (Right to Buy) 16.21 2019-04-01 4 A 0 17491 0.00 A 2022-02-01 Common Stock 17491 17491 D Employee Stock Option (Right to Buy) 14.40 2019-04-01 4 A 0 27773 0.00 A 2023-02-01 Common Stock 27773 27773 D Employee Stock Option (Right to Buy) 15.54 2019-04-01 4 A 0 9930 0.00 A 2024-03-03 Common Stock 9930 9930 D Employee Stock Option (Right to Buy) 17.20 2019-04-01 4 A 0 13125 0.00 A 2025-03-16 Common Stock 13125 13125 D Employee Stock Option (Right to Buy) 17.20 2019-04-01 4 A 0 2500 0.00 A 2025-03-16 Common Stock 2500 2500 D Employee Stock Option (Right to Buy) 11.28 2019-04-01 4 A 0 50801 0.00 A 2026-03-01 Common Stock 50801 50801 D Employee Stock Option (Right to Buy) 18.46 2019-04-01 4 A 0 113430 0.00 A 2027-02-27 Common Stock 113430 113430 D Employee Stock Option (Right to Buy) 16.02 2019-04-01 4 A 0 141007 0.00 A 2028-02-21 Common Stock 141007 141007 D Employee Stock Option (Right to Buy) 14.20 2019-04-01 4 A 0 514786 0.00 A 2029-01-29 Common Stock 514786 514786 D In connection with the separation (the "Separation") of Cyclerion Therapeutics, Inc. ("Cyclerion") from Ironwood Pharmaceuticals, Inc. ("Ironwood"), the reporting person received Cyclerion shares representing an equitable adjustment of Ironwood shares held by the reporting person prior to the Separation. Represents options to purchase shares of Cyclerion common stock granted to the reporting person in connection with the Separation. This option, granted as an annual performance award, is presently exercisable in full. This option to purchase 25,212 shares vests in equal installments upon achievement of certain regulatory and commercial milestones. The option has vested as to 2,500 shares as of the date hereof. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2016. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2017. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2018. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2019. /s/ Larry Miller, Attorney-in-Fact 2019-04-03