MBX Biosciences, Inc. (MBX) Institutional Ownership

Ownership Summary

MBX Biosciences, Inc. (NASDAQ:MBX) has 156 institutional investors with active 13F positions as of March 2026.

• They owned 112.8% of outstanding stock in March 2026, down from 129.6% the prior quarter.
• Their total shares held in MBX increased 19.16% quarter over quarter, and separately, investors owning MBX Biosciences increased 95.0% from a year ago.
• Of these 156 holders, 84 added to their stakes in MBX Biosciences, 49 trimmed positions, and 23 made no changes.
• The aggregate institutional position in MBX Biosciences amounted to 52.55Mn shares as of March 2026, up by 8.45Mn shares quarter on quarter, and up 16.47Mn shares year over year.
• Frazier Life Sciences Management, L.P. leads ownership in MBX with 6.65Mn shares as of March 31, 2026, equal to 14.28% of outstanding shares.
• The largest buyers of MBX Biosciences for the quarter ending March 2026 were FMR LLC (2.92Mn), Polar Capital Holdings Plc (1.62Mn), VANGUARD CAPITAL MANAGEMENT LLC (1.48Mn), Aaron Wealth Advisors LLC (1.1Mn), PRICE T ROWE ASSOCIATES INC /MD/ (1.03Mn).
• The biggest sellers of MBX Biosciences for the quarter ending March 2026 included EcoR1 Capital, LLC (1.35Mn), Deep Track Capital, LP (492.22K), DRIEHAUS CAPITAL MANAGEMENT LLC (389.95K), D. E. Shaw & Co., Inc. (382.95K), ORBIMED ADVISORS LLC (297.32K).
• Per Business Quant data, the top 10 holders of MBX Biosciences for the quarter ending March 2026 are Frazier Life Sciences Management, L.P. (6.65Mn), ORBIMED ADVISORS LLC (3.64Mn), NEA Management Company, LLC (3.61Mn), WELLINGTON MANAGEMENT GROUP LLP (3.19Mn), BlackRock, Inc. (2.94Mn), FMR LLC (2.94Mn), Deep Track Capital, LP (2.76Mn), NVP Associates, LLC (2.14Mn), Polar Capital Holdings Plc (1.62Mn), BRAIDWELL LP (1.49Mn).