Welcome to our dedicated page for Korro Bio SEC filings (Ticker: KRRO), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Korro Bio, Inc. filings document the regulatory record of a biopharmaceutical company developing RNA-editing genetic medicines through its OPERA® platform. Its 8-K reports disclose operating and financial results, corporate presentations, clinical and regulatory program updates, capital-structure activity, and material events tied to its RNA-editing pipeline.
The company’s filings also cover proxy governance, executive compensation, equity incentive and inducement arrangements, employment agreements, and material collaboration and license agreements. Program-related disclosures focus on KRRO-121, hyperammonemia in urea cycle disorders and hepatic encephalopathy, GalNAc-conjugated oligonucleotide research, alpha-1 antitrypsin deficiency, risk factors, and the financing and governance framework supporting Korro Bio’s development-stage operations.
Driehaus Capital Management LLC has amended its ownership report for Korro Bio, Inc., stating that it now beneficially owns 0 shares of Korro Bio common stock, representing 0% of the class as of 12/31/2025. The filer confirms it holds no sole or shared voting or dispositive power over any Korro Bio shares and notes this is an exit filing indicating ownership of 5 percent or less of the company’s common stock.
Nantahala Capital Management, LLC and its principals reported a significant ownership stake in Korro Bio, Inc. As of December 31, 2025, they may be deemed to beneficially own 600,000 shares of Korro Bio common stock, representing 6.37% of the outstanding shares.
The shares are held by funds and separately managed accounts under Nantahala’s control, with Nantahala, Wilmot B. Harkey, and Daniel Mack sharing voting and dispositive power over all 600,000 shares. They state that the position is held in the ordinary course of business and not for the purpose of changing or influencing control of Korro Bio.
FMR LLC and Abigail P. Johnson report beneficial ownership of 37,857 shares of Korro Bio Inc. common stock, representing 0.4% of the outstanding class as of the event date of December 31, 2025.
FMR LLC has sole voting power over 33,257 shares and sole dispositive power over 37,857 shares. Abigail P. Johnson reports sole dispositive power over the same 37,857 shares, with no voting power. The filing states the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of Korro Bio. One or more other persons may receive dividends or sale proceeds from these shares, but no such person holds more than five percent of the common stock.
Korro Bio, Inc. reported that President and CEO Ram Aiyar received new equity awards on February 2, 2026. He was granted 40,000 shares of common stock through restricted stock units under the 2023 Stock Option and Incentive Plan, vesting 50% on August 3, 2026 and 50% on February 1, 2027, subject to continued service.
He was also granted a stock option for 80,000 shares of common stock at an exercise price of $13.05, vesting in 48 equal monthly installments starting February 2, 2026 and expiring February 1, 2036. Separately, 4,613 common shares are held indirectly by The Ram Aiyar Irrevocable Trust, for which he serves as trustee and disclaims full beneficial ownership.
Korro Bio, Inc. reported that its Chief Scientific Officer, Vincent Loic A, received a grant of stock options on February 2, 2026. The award covers 35,000 stock options with an exercise price of $13.05 per share for Korro Bio common stock.
The options vest in 48 equal monthly installments starting on February 2, 2026, and each monthly vesting is conditioned on the executive’s continued service on that date. After this grant, the officer beneficially owns 35,000 derivative securities directly.
Korro Bio, Inc. reported that Senior Vice President of Finance Dolan Oliver received a stock option award. On February 2, 2026, Oliver was granted an option to buy 15,000 shares of Korro Bio common stock at an exercise price of $13.05 per share, expiring February 1, 2036.
The option vests in 48 equal monthly installments starting February 2, 2026, contingent on Oliver’s continued service with the company on each vesting date. After this grant, Oliver beneficially owns 15,000 derivative securities directly.
Korro Bio, Inc. reported that its General Counsel, Jeffrey Cerio, received a grant of stock options covering 23,000 shares of common stock. The options have an exercise price of $13.05 per share and were awarded on February 2, 2026.
These options vest in 48 equal monthly installments starting on February 2, 2026, and each vesting date requires Mr. Cerio to remain in service with the company. Following this grant, he beneficially holds options for 23,000 shares, all in direct ownership.
Korro Bio, Inc. reported that Chief Operating Officer Todd Chappell received a stock option award for 38,000 derivative securities described as a stock option (right to buy) common stock. The option has an exercise price of $13.05 per share and was granted on February 2, 2026.
The grant was made for no purchase price and leaves Chappell with 38,000 stock options beneficially owned directly. These options expire on February 1, 2036 and vest in 48 equal monthly installments starting February 2, 2026, conditioned on his continued service at each vesting date.
The Vanguard Group has filed a Schedule 13G reporting a passive ownership stake in Korro Bio Inc. Vanguard reports beneficial ownership of 489,639 shares of Korro Bio common stock, representing 5.19% of the class as of the event date.
Vanguard lists shared voting power over 43,589 shares and shared dispositive power over 489,639 shares, with no sole voting or dispositive power. The filing states the securities are held in the ordinary course of business and not for the purpose of changing or influencing control of Korro Bio.
Korro Bio, Inc. reported that it hosted a virtual Analyst Day on January 27, 2026. The company made selected presentation slides from this event publicly available by attaching them as an exhibit to this report. These slides are intended to provide additional background and strategic information about Korro Bio’s business for analysts and investors.