BlackRock, Inc. filed an amended Schedule 13G with the SEC on October 27, 2026, disclosing beneficial ownership of 13,013,495 shares of Cabaletta Bio, Inc. common stock as of September 30, 2026.

Key Highlights

  • Aggregate beneficial ownership: BlackRock reported holding 13,013,495 shares of Cabaletta Bio common stock, representing 7.7% of the class.
  • Sole voting power: BlackRock reported sole voting power over 12,756,356 shares.
  • Sole dispositive power: BlackRock reported sole dispositive power over 13,013,495 shares.
  • No shared voting or dispositive power: Both shared voting power and shared dispositive power are reported as 0.
  • Triggering event date: The date of the event requiring this filing is stated as September 30, 2026.
  • Filer type: BlackRock, Inc. is identified as a holding company (HC) organized in Delaware, with its principal office at 50 Hudson Yards, New York, NY 10001.

BlackRock's Amended Beneficial Ownership Position in Cabaletta Bio

BlackRock, Inc. filed Amendment No. 1 to its Schedule 13G regarding its holdings in Cabaletta Bio, Inc. (CUSIP 12674W109), whose principal executive offices are located at 2929 Arch Street, Suite 600, Philadelphia, PA 19104. According to the filing, the position reflects securities beneficially owned by certain business units of BlackRock and its subsidiaries and affiliates, described in the filing as the "Reporting Business Units," consistent with SEC Release No. 34-39538 dated January 12, 1998. The filing notes that it does not include securities, if any, beneficially owned by other business units whose beneficial ownership is disaggregated from that of the Reporting Business Units in accordance with that release.

BlackRock disclosed aggregate beneficial ownership of 13,013,495 shares, equal to 7.7% of the outstanding common stock of Cabaletta Bio. Of those shares, 12,756,356 are subject to sole voting power, while the remaining shares carry no shared voting or dispositive arrangements, according to the filing. The identity and classification of the relevant subsidiaries through which the position is held are stated to be provided in Exhibit 99 attached to the filing.

Regarding the right to receive dividends or sale proceeds, the filing states that "various persons have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of the common stock of Cabaletta Bio, Inc." and that "no one person's interest in the common stock of Cabaletta Bio, Inc. is more than five percent of the total outstanding common shares." The filing was signed by Spencer Fleming, Managing Director of BlackRock, Inc., on October 27, 2026, and certifies that the securities were acquired and held in the ordinary course of business.

What Was Disclosed

BlackRock, Inc. filed an amended Schedule 13G reporting 13,013,495 shares of Cabaletta Bio, Inc. common stock beneficially owned as of September 30, 2026, representing 7.7% of the class, with sole voting power over 12,756,356 shares and sole dispositive power over the full reported position.