Cyclerion Therapeutics, Inc. (CYCN) Institutional Ownership

Ownership Summary

Cyclerion Therapeutics, Inc. (NASDAQ:CYCN) showed up in the 13F filings of 19 institutional investors as of December 2025.

• Their combined ownership stood at 9.2% of outstanding shares in December 2025, up from 8.0% in September 2025.
• They increased total shares held in Cyclerion Therapeutics by 37.64% from the prior quarter, while the number of investors in CYCN decreased 5.0% year over year.
• Of these 19 funds, 9 grew their exposure to Cyclerion Therapeutics, 3 cut back, and 7 maintained positions.
• In total, institutional investors held 296.26K shares in Cyclerion Therapeutics as of December 2025, up by 81.02K shares quarter on quarter, and down 87.01K shares year over year.
• Siren, L.L.C. holds the largest position in CYCN at 115.6K shares as of December 31, 2025, or 3.58% of shares outstanding.
• Leading buyers of Cyclerion Therapeutics shares for the quarter ending December 2025 were TWO SIGMA ADVISERS, LP (28.3K), TWO SIGMA INVESTMENTS, LP (28.26K), XTX Topco Ltd (10.03K), Citigroup Inc (8.2K), GEODE CAPITAL MANAGEMENT, LLC (6.14K).
• The largest sales of CYCN for the quarter ending December 2025 came from Morgan Stanley (648), Siren, L.L.C. (552), FMR LLC (6).
• According to Business Quant data, leading holders of CYCN for December 2025 are Siren, L.L.C. (115.6K), GEODE CAPITAL MANAGEMENT, LLC (43.3K), TWO SIGMA INVESTMENTS, LP (41.56K), TWO SIGMA ADVISERS, LP (28.3K), VANGUARD GROUP INC (23.49K), BlackRock, Inc. (16.8K), XTX Topco Ltd (10.03K), Citigroup Inc (8.2K), FMR LLC (4.74K), Tower Research Capital LLC (TRC) (3.15K).