MBX Biosciences, Inc. - Common Stock, par value $0.0001 per share (MBX) Institutional Ownership

13F Institutional Holders and Ownership History from Q3 2024 to Q4 2025

Type / Class
Equity / Common Stock, par value $0.0001 per share
Symbol
MBX on Nasdaq
Shares outstanding
46,413,000
Price per share
$31.54
All holders as of 30 Sep 2025
Q3 2025
Total 13F shares
47,790,065
Total reported value
$836,364,494
% of total 13F portfolios
0%
Share change
+10,949,133
Value change
+$203,956,800
Number of holders
117
Price from insider filings
$31.54
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Significant Owners of MBX Biosciences, Inc. - Common Stock, par value $0.0001 per share (MBX) based on Schedule 13D/G filings

Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
Frazier Life Sciences Public Fund, L.P. 12% -14% $72,562,680 +$9,264,602 5,224,095 +15% Patrick J. Heron 26 Sep 2025
WELLINGTON MANAGEMENT GROUP LLP 11% +57% $84,412,721 +$44,744,691 4,823,336 +113% Wellington Management Group LLP 30 Sep 2025
ORBIMED ADVISORS LLC 9% $55,600,100 4,002,887 ORBIMED ADVISORS LLC 26 Sep 2025
New Enterprise Associates 17, L.P. 8.1% $63,340,795 3,619,474 Edward T. Mathers 06 Nov 2025
Deep Track Capital, LP 6.6% $30,399,543 2,188,592 Deep Track Capital, LP 30 Jun 2025
Norwest Venture Partners XVI, LP 4.8% $29,738,337 2,140,989 Tiba Aynechi 26 Sep 2025
Wellington Biomedical Innovation Master Investors (Cayman) II L.P. 4.5% $35,304,395 2,017,394 Wellington Biomedical Innovation Master Investors (Cayman) II, L.P. 30 Sep 2025
Hawryluk P. Kent 4.3% $34,925,782 1,995,759 P. Kent Hawryluk 30 Sep 2025

As of 30 Sep 2025, 117 institutional investors reported holding 47,790,065 shares of MBX Biosciences, Inc. - Common Stock, par value $0.0001 per share (MBX). This represents 103% of the company’s total 46,413,000 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of MBX Biosciences, Inc. - Common Stock, par value $0.0001 per share (MBX) together control 94% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
Frazier Life Sciences Management, L.P. 14% 6,652,013 +11% 3.5% $116,410,228
WELLINGTON MANAGEMENT GROUP LLP 10% 4,823,336 +113% 0.01% $84,408,382
ORBIMED ADVISORS LLC 8.6% 4,002,887 0% 1.7% $70,050,523
NEA Management Company, LLC 7.8% 3,614,486 0% 3.5% $63,253,505
Deep Track Capital, LP 6.8% 3,150,000 +44% 1.5% $55,125,000
NVP ASSOCIATES, LLC 4.6% 2,136,335 0% 23% $37,385,863
EcoR1 Capital, LLC 4.6% 2,123,604 +85% 1.8% $37,163,070
Kynam Capital Management, LP 4.3% 2,000,000 2.6% $35,000,000
BlackRock, Inc. 4.2% 1,957,461 +94% 0% $34,255,569
VANGUARD GROUP INC 3.6% 1,677,362 +61% 0% $29,353,836
Driehaus Capital Management LLC 3.3% 1,539,639 -2.1% 0.19% $26,943,683
FRANKLIN RESOURCES INC 2.8% 1,307,288 +164% 0.01% $22,877,540
Cormorant Asset Management, LP 2.6% 1,225,000 +75% 1.5% $21,437,500
Woodline Partners LP 2.6% 1,201,150 +33% 0.1% $21,020,125
CITADEL ADVISORS LLC 2.1% 996,083 0.01% $17,431,453
PRICE T ROWE ASSOCIATES INC /MD/ 2.1% 954,726 -29% 0% $16,709,000
Parkman Healthcare Partners LLC 1.7% 773,304 -11% 1.5% $13,532,820
MILLENNIUM MANAGEMENT LLC 1.4% 655,416 -15% 0.01% $11,469,780
TCG Crossover Management, LLC 1.4% 650,000 0% 0.56% $11,375,000
Point72 Asset Management, L.P. 1.4% 627,667 -36% 0.02% $10,984,173
GEODE CAPITAL MANAGEMENT, LLC 1% 473,932 +36% 0% $8,295,948
GOLDMAN SACHS GROUP INC 0.77% 358,121 0% $6,267,118
STATE STREET CORP 0.69% 319,274 +20% 0% $5,587,295
Schonfeld Strategic Advisors LLC 0.61% 282,677 -55% 0.03% $4,946,847
Rock Springs Capital Management LP 0.61% 282,624 0.29% $4,945,920

Institutional Holders of MBX Biosciences, Inc. - Common Stock, par value $0.0001 per share (MBX) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2025 Q4 5,066 $159,494 +$150,064 $31.54 3
2025 Q3 47,790,065 $836,364,494 +$203,956,800 $17.50 117
2025 Q2 36,839,365 $420,338,016 +$15,668,027 $11.41 87
2025 Q1 35,666,401 $263,220,263 +$14,436,866 $7.38 79
2024 Q4 32,941,714 $606,485,118 +$46,248,268 $18.43 63
2024 Q3 30,280,441 $783,422,213 +$783,375,221 $25.98 44