T. Rowe Price Investment Management, Inc. filed Amendment No. 6 to its Schedule 13G with the SEC on November 6, 2026, disclosing beneficial ownership of 28,138,417 shares of Cabaletta Bio Inc. common stock as of October 31, 2026.

Key Highlights

  • Aggregate beneficial ownership: T. Rowe Price Investment Management, Inc. reported beneficial ownership of 28,138,417 shares of Cabaletta Bio Inc. common stock.
  • Percent of class: The reported holdings represent 13.1% of the outstanding class of common stock (CUSIP 12674W109).
  • Sole voting power: The filing states sole voting power over 28,048,173 shares, with shared voting power of zero.
  • Sole dispositive power: Sole dispositive power is reported over 28,138,417 shares, with shared dispositive power of zero.
  • T. Rowe Price Small-Cap Value Fund interest: According to the filing, T. Rowe Price Small-Cap Value Fund holds an interest in 15,367,961 of the reported shares, representing 7.1% of the class.
  • Triggering event date: The date of the event requiring this filing is stated as October 31, 2026.

T. Rowe Price Investment Management Discloses Amended Ownership Position in Cabaletta Bio

T. Rowe Price Investment Management, Inc., organized in Maryland and acting as an investment adviser, filed Amendment No. 6 to Schedule 13G with the SEC on November 6, 2026, covering its holdings in Cabaletta Bio Inc. (NASDAQ:CABA), headquartered at 2929 Arch Street, Suite 600, Philadelphia, PA 19104. The filing identifies the reporting person as an investment adviser and lists its principal business address as 1307 Point Street, Baltimore, MD 21231. The statement was signed by Ellen York, Vice President, on November 6, 2026.

According to the filing, T. Rowe Price Investment Management, Inc. beneficially owns 28,138,417 shares of Cabaletta Bio common stock, representing 13.1% of the class. Of that total, the firm reports sole voting power over 28,048,173 shares and sole dispositive power over the full 28,138,417 shares. No shared voting or dispositive power is reported. The filing further discloses that T. Rowe Price Small-Cap Value Fund, for which T. Rowe Price Investment Management, Inc. serves as investment adviser, holds an interest in 15,367,961 of the reported shares, representing 7.1% of the class.

The filing states that T. Rowe Price Investment Management does not serve as custodian of client assets, and that "the ultimate power to direct the receipt of dividends paid with respect to, and the proceeds from the sale of, such securities, is vested in the individual and institutional clients." The filing also notes that "any and all discretionary authority which has been delegated to Price Investment Management may be revoked in whole or in part at any time." Additionally, the filing certifies 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."

What Was Disclosed

T. Rowe Price Investment Management, Inc. disclosed beneficial ownership of 28,138,417 shares, or 13.1%, of Cabaletta Bio Inc. common stock in Amendment No. 6 to Schedule 13G, with a triggering event date of October 31, 2026, and no shared voting or dispositive power reported.