Cyclerion Therapeutics, Inc. (CYCN) Institutional Ownership

Ownership Summary

Recent 13F filings as of December 2025 show that 19 institutional investors hold a position in Cyclerion Therapeutics, Inc. (NASDAQ:CYCN).

• Cyclerion Therapeutics saw its institutional ownership percentage rose to 10.1% in December 2025 from 8.8% in September 2025.
• The company experienced a 37.66% quarterly change in institutional shares held, alongside a decrease of 5.00% in total owners annually.
• Of these 19 institutional investors, 9 increased their holdings in Cyclerion Therapeutics, while 3 of them reduced positions, and 7 investors maintained their exposure.
• This class of investors increased its holdings in Cyclerion Therapeutics to 296.25K shares for the 13F-cycle ending December 2025, up by 81.04K shares quarter on quarter, and down 85.82K shares year over year.
• With 115.60K shares, Siren, L.L.C. commands the largest institutional position in Cyclerion Therapeutics as of December 31, 2025, equating to 3.94% of the company.
• Among the most significant buyers of Cyclerion Therapeutics during December 2025 were TWO SIGMA ADVISERS, LP (28.30K), TWO SIGMA INVESTMENTS, LP (28.26K), XTX Topco Ltd (10.03K), CITIGROUP INC (8.20K), GEODE CAPITAL MANAGEMENT, LLC (6.14K).
• Leading sellers of Cyclerion Therapeutics stock in December 2025 included MORGAN STANLEY (648), Siren, L.L.C. (552), FMR LLC (6).
• The top 10 institutional holders of Cyclerion Therapeutics for the quarter ending December 2025 included Siren, L.L.C. (115.60K), GEODE CAPITAL MANAGEMENT, LLC (43.30K), TWO SIGMA INVESTMENTS, LP (41.55K), TWO SIGMA ADVISERS, LP (28.30K), VANGUARD GROUP INC (23.49K), BlackRock, Inc. (16.80K), XTX Topco Ltd (10.03K), CITIGROUP INC (8.20K), FMR LLC (4.74K), Tower Research Capital LLC (TRC) (3.15K).