MBX Biosciences, Inc. (MBX) Institutional Ownership

Ownership Summary

A total of 118 institutions have reported a stake in MBX Biosciences, Inc. (NASDAQ:MBX) as of September 2025, according to recent 13F filings with the SEC.

• MBX Biosciences saw its institutional ownership percentage rose to 143.7% in September 2025 from 110.4% in June 2025.
• Institutional share ownership changed by 36.52% QoQ, while the number of institutional owners saw an increase of 162.22% YoY.
• Among the 118 institutional holders of MBX Biosciences, 68 added to their stakes while 32 trimmed their positions and 18 held steady.
• Collectively, institutional investors increased their stake in MBX Biosciences to 48.27Mn shares as of September 2025, a change that is up by 12.91Mn shares quarter on quarter and up 17.96Mn shares year over year.
• Frazier Life Sciences Management, L.P. continues to be the largest institutional holder of MBX Biosciences as of September 30, 2025, with a position of 6.65Mn shares, representing 19.80% of the company's outstanding stock.
• Among the most significant buyers of MBX Biosciences during September 2025 were WELLINGTON MANAGEMENT GROUP LLP (2.56Mn), Kynam Capital Management, LP (2.00Mn), EcoR1 Capital, LLC (973.81K), Deep Track Capital, LP (961.41K), BlackRock, Inc. (945.91K).
• Leading sellers of MBX Biosciences stock in September 2025 included PRICE T ROWE ASSOCIATES INC /MD/ (392.18K), Schonfeld Strategic Advisors LLC (348.74K), Point72 Asset Management, L.P. (346.12K), MILLENNIUM MANAGEMENT LLC (137.72K), Parkman Healthcare Partners LLC (98.63K).
• The top 10 institutional holders of MBX Biosciences for the quarter ending September 2025 included Frazier Life Sciences Management, L.P. (6.65Mn), WELLINGTON MANAGEMENT GROUP LLP (4.82Mn), ORBIMED ADVISORS LLC (4.00Mn), NEA Management Company, LLC (3.61Mn), Deep Track Capital, LP (3.15Mn), NVP Associates, LLC (2.14Mn), EcoR1 Capital, LLC (2.12Mn), Kynam Capital Management, LP (2.00Mn), BlackRock, Inc. (1.96Mn), VANGUARD GROUP INC (1.68Mn).