MPM BioImpact LLC filed a Schedule 13G with the SEC on November 13, 2026, reporting beneficial ownership of 1,667,272 shares of Corbus Pharmaceuticals Holdings, Inc. common stock, representing 8.6% of the class, as of September 30, 2026.

Key Highlights

  • Beneficial ownership reported: MPM BioImpact LLC disclosed ownership of 1,667,272 shares of Corbus Pharmaceuticals Holdings, Inc. common stock.
  • Percent of class: The 1,667,272 shares represent 8.6% of the outstanding class, according to the filing.
  • Sole voting and dispositive power: MPM BioImpact LLC reported sole power to vote and to dispose of all 1,667,272 shares, with no shared voting or dispositive power reported.
  • Triggering date: The event requiring the filing occurred on September 30, 2026.
  • Filer type: MPM BioImpact LLC is classified as an investment adviser (type "IA") and is organized in Delaware, with its principal office at 399 Boylston Street, Suite 1100, Boston, MA 02116.
  • Signing officer: The statement was signed by Christopher Wolf, Chief Financial Officer of MPM BioImpact LLC, on November 13, 2026.

MPM BioImpact LLC Reports Ownership Position in Corbus Pharmaceuticals as of September 30, 2026

According to the Schedule 13G filed on November 13, 2026, MPM BioImpact LLC, a Delaware-organized investment adviser, reported beneficial ownership of 1,667,272 shares of Corbus Pharmaceuticals Holdings, Inc. (NASDAQ:CRBP) common stock, par value $0.0001 per share (CUSIP: 21833P301). The filing states that the event requiring the submission of this statement occurred on September 30, 2026. Corbus Pharmaceuticals Holdings, Inc. is located at 500 River Ridge Drive, Norwood, MA 02062, according to the filing.

The filing discloses that MPM BioImpact LLC holds sole voting power and sole dispositive power over all 1,667,272 shares. No shared voting power or shared dispositive power was reported. The 1,667,272 shares represent 8.6% of the class of common stock, as stated in the filing. Items 5 through 9 of the Schedule 13G, covering ownership of 5% or less, ownership on behalf of another person, subsidiary identification, group membership, and dissolution of group, were each reported as "Not Applicable."

The filing includes the standard Schedule 13G certification, in which MPM BioImpact LLC, through its Chief Financial Officer Christopher Wolf, certified "that the securities referred to above 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 of the securities." The statement was signed by Christopher Wolf on November 13, 2026.

What Was Disclosed

MPM BioImpact LLC, a Delaware investment adviser, filed a Schedule 13G disclosing beneficial ownership of 1,667,272 shares, equal to 8.6% of Corbus Pharmaceuticals Holdings, Inc. common stock, as of September 30, 2026, with sole voting and dispositive power over all reported shares.