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Korsana Biosciences, Inc. (CYCN) has a new large shareholder group led by General Atlantic investment entities, which together report beneficial ownership of 3,201,131 shares of common stock, representing 6.8% of the company. The position is held through General Atlantic (KB), L.P., which owns 1,366,242 shares of common stock and a Pre-Funded Warrant to purchase an additional 1,834,889 shares.
The 6.8% ownership is calculated against an aggregate base of 47,376,314 shares, including shares issuable upon warrant exercise. Multiple General Atlantic partnerships and co-investment vehicles may be deemed to share voting and dispositive power, and warrant exercises are limited by a 9.99% beneficial-ownership blocker.
Korsana Biosciences, Inc. (CYCN) director Errol B. De Souza has filed a notice of proposed sale under Rule 144 for 2,139 shares of common stock of the company, to be handled through Morgan Stanley Smith Barney LLC on NASDAQ.
The shares relate to restricted stock that vested between November 30, 2023 and September 1, 2024, and the filing lists an approximate aggregate market value of $74,843.61 for the securities covered by this notice as of September 18, 2026.
Korsana Biosciences, Inc. (CYCN) is reported to have a significant shareholder, Wellington Biomedical Innovation Master Investors (Cayman) II, L.P., which has filed as a passive holder on a Schedule 13G. The fund reports beneficial ownership of 2,775,788 shares of common stock, representing 6.10% of the class.
The filing states the holder has shared power to vote and dispose of all 2,775,788 shares, with no sole voting or dispositive power. This positions the Wellington-affiliated fund as a notable institutional investor in Korsana Biosciences without indicating any change of control intent.
Korsana Biosciences, Inc. (CYCN) received a Schedule 13D from Venrock-affiliated funds and individuals reporting beneficial ownership of 4,552,277 shares of common stock, or an effective 9.995% stake subject to a 9.99% beneficial ownership cap. The position includes common stock, Series B non-voting preferred shares, pre-funded warrants and options.
The group invested $134,843,200 into Old Korsana between November 2024 and the September 8, 2026 merger, acquiring preferred stock, common stock and pre-funded warrants that converted into Korsana securities at an exchange ratio of 0.2074 per Old Korsana common share. Pre-funded warrants are exercisable at $0.0001 per share with no expiration but are blocked, along with Series B Preferred, from conversion above the ownership cap, adjustable up to 19.99% on 61 days’ notice. Venrock partners Nimish Shah and Andrew Gottesdiener serve on Korsana’s board, and certain Venrock entities and insiders are subject to 180-day lock-up agreements following the merger closing.
Cyclerion Therapeutics, Inc. (now named Korsana Biosciences, Inc.) received a Schedule 13D from Fairmount Funds Management LLC and affiliates reporting significant ownership and governance rights. Fairmount, Fairmount Healthcare Fund II L.P., Fairmount Healthcare Co-Invest VI L.P., Peter Harwin and Tomas Kiselak together have voting and dispositive power over 9,103,729 shares of common stock, representing 19.99% of the outstanding common stock as of September 8, 2026. These shares are primarily held through Fund II (6,911,174 shares) and Co-Invest (2,192,555 shares), plus options held by Mr. Kiselak that are exercisable within 60 days.
The group also holds additional upside through Series B Non-Voting Convertible Preferred Stock convertible into 2,074,000 common shares and Pre-Funded Warrants for 66,436 shares, but these are subject to a beneficial ownership limitation of 19.99%, with a potential automatic reduction to 9.99% once Fairmount and its affiliates beneficially own 9.0% or less. The filing details the recently completed reverse-merger with Pre-Merger Korsana, a reverse stock split, and the designation of Series B Preferred Stock, which can elect four “Preferred Directors” with three board votes each and has strong consent rights over major corporate actions.
Fairmount-led funds invested heavily in prior Korsana financings and a $380.0 million pre-closing financing commitment and paid an aggregate $99,999,973 for common stock and pre-funded warrants, plus $12,500,000 for Series B Preferred. The investors are subject to 180-day lock-up agreements after the merger effective time, and the company has agreed under a Registration Rights Agreement to file a resale registration statement within 30 days of the merger closing for the benefit of these investors.
Cyclerion Therapeutics, Inc. (now Korsana Biosciences, Inc., Nasdaq: KRSA) completed its reverse-merger with private Korsana and a 1-for-7 reverse stock split on September 8, 2026, transforming the former shell into a neurology-focused biotech. Following a $380 million private financing completed immediately before closing, the combined company reports approximately $475 million in cash and equivalents, which it states is expected to fund operations into 2029. Korsana securityholders now own about 98.83% of the fully diluted capital stock, while legacy Cyclerion holders own about 1.17%, and total common stock and equivalents are about 55.1 million. Pre‑merger Cyclerion holders also receive non‑transferable contingent value rights tied to 100% of net proceeds from future sales or other dispositions of specified legacy assets. Governance shifts to a six‑member board dominated by Series B preferred investors, who elect four “Preferred Directors” with three votes each, and new leadership appointments include Jonathan Violin, Ph.D. as Chief Executive Officer and President.
Cyclerion Therapeutics, Inc. (CYCN) reported that director Michelle Patricia Pernice received a grant of stock options covering 48,445 shares of common stock on September 9, 2026. The options have an exercise price of $26.20 per share, vest in equal monthly installments through September 9, 2029, and expire on September 9, 2036. Following this grant, she holds options on 48,445 shares directly, and no Rule 10b5-1 trading plan is reported.
Cyclerion Therapeutics, Inc. (CYCN) reported that director Nimish P. Shah received a grant of stock options on September 9, 2026 to acquire 48,445 shares of common stock at an exercise price of $26.20 per share. These options vest in equal monthly installments through September 9, 2029 and expire on September 9, 2036. According to an agreement with Venrock Management, LLC, the option and underlying shares are held for the sole benefit of Venrock Management, which is entitled to the underlying shares, and Shah disclaims beneficial ownership except to the extent of his pecuniary interest.
Cyclerion Therapeutics, Inc. (CYCN) reported that investment entities associated with Fairmount Funds Management LLC received a compensatory grant of stock options indirectly held through Tomas Kiselak. On September 9, 2026, an option for 48,445 shares of common stock was awarded at an exercise price of $26.20 per share, with no cash paid for the grant. The option vests in equal monthly installments through September 9, 2029, and expires on September 9, 2036. The filing states that Kiselak holds the option for one or more Fairmount-managed investment vehicles, and Fairmount, Peter Harwin, and Kiselak each disclaim beneficial ownership except to the extent of any pecuniary interest.
Cyclerion Therapeutics, Inc. (CYCN) reported that director Andrew Gottesdiener received a grant of stock options covering 48,445 shares of common stock on September 9, 2026. The options have an exercise price of $26.20 per share, expire on September 9, 2036, and vest in equal monthly installments through September 9, 2029, subject to his continued service.
Under an agreement with Venrock Management, LLC, the option and underlying shares are held for the sole benefit of Venrock Management, which is entitled to the underlying shares; Gottesdiener and Venrock Management each may be deemed indirect beneficial owners, and Gottesdiener disclaims beneficial ownership except to the extent of his pecuniary interest. No Rule 10b5-1 trading plan is reported.