BlackRock Portfolio Management LLC filed an amended beneficial ownership statement with the SEC on October 27, 2026, disclosing a 9.1% stake in Keros Therapeutics, Inc. (NASDAQ:KROS) as of September 30, 2026.

Key Highlights

  • Aggregate beneficial ownership: BlackRock Portfolio Management LLC reported beneficial ownership of 1,813,870 shares of Keros Therapeutics common stock.
  • Percent of class: The reported position represents 9.1% of the outstanding common shares, according to the filing.
  • Sole voting power: BlackRock Portfolio Management LLC holds sole voting power over 1,575,150 shares.
  • Sole dispositive power: The filer reported sole dispositive power over all 1,813,870 shares, with no shared dispositive power reported.
  • Event date: The triggering event requiring the filing occurred on September 30, 2026.
  • Amendment: This is Amendment No. 1 to a prior beneficial ownership statement for the same issuer and security class.

BlackRock Portfolio Management's Amended Position in Keros Therapeutics

According to the filing, BlackRock Portfolio Management LLC, a Delaware-organized entity headquartered at 50 Hudson Yards, New York, NY 10001, reported aggregate beneficial ownership of 1,813,870 shares of Keros Therapeutics, Inc. common stock (CUSIP 492327101). The filing identifies the reporting person as a holding company ("HC" type) and notes that the disclosed position reflects securities beneficially owned by certain business units of BlackRock, Inc. and its subsidiaries and affiliates, as described under SEC Release No. 34-39538 (January 12, 1998). The filing states that it "does not include securities, if any, beneficially owned by other business units whose beneficial ownership of securities are disaggregated from that of the Reporting Business Units in accordance with such release."

Keros Therapeutics, Inc. is a biopharmaceutical company whose principal executive offices are located at 1050 Waltham Street, Suite 302, Lexington, MA 02421, according to the filing. The filing discloses that various persons have the right to receive or direct dividends or sale proceeds from the common stock of Keros Therapeutics, Inc., and that "no one person's interest in the common stock of Keros Therapeutics, Inc. is more than five percent of the total outstanding common shares." The filer certified that the securities were "acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer." Managing Director Spencer Fleming signed on behalf of BlackRock Portfolio Management LLC on October 27, 2026.

What Was Disclosed

BlackRock Portfolio Management LLC filed an amendment disclosing beneficial ownership of 1,813,870 shares of Keros Therapeutics common stock, representing 9.1% of the class, with sole voting power over 1,575,150 shares and sole dispositive power over the full position, as of September 30, 2026.