Latest Period
Q4 2025
Security Snapshot
MBX Biosciences, Inc. - COMMON STOCK (MBX) Institutional Ownership
CUSIP: 55287L101
13F Institutional Holders and Ownership History from Q3 2024 to Q1 2026
Institutions Reporting
136
Shares (Excl. Options)
48,426,905
Price
$31.54
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- Type / Class
- Equity / COMMON STOCK
- Symbol
- MBX on Nasdaq
- Shares outstanding
- 47,365,871
- Price per share
- $29.85
- All holders as of 31 Dec 2025
- Q4 2025
- Total 13F shares
- 48,426,905
- Total reported value
- $1,527,200,912
- % of total 13F portfolios
- 0%
- Share change
- -32,964
- Value change
- +$34,719,624
- Number of holders
- 136
- Price from insider filings
- $29.85
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors
Quick Takeaways
- MBX - MBX Biosciences, Inc. - COMMON STOCK is tracked under CUSIP 55287L101.
- 136 institutions reported positions in Q4 2025.
- 10 significant owners is listed from Schedule 13D/13G reporting.
What Changed
- Holder count moved from 136 to 49 between Q4 2025 and Q1 2026.
- Reported value moved from $1,527,200,912 to $132,176,887.
Why This Matters
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Source Evidence
Source: SEC Form 13F
Open SEC Evidence
Latest holder context comes from 136 institutions filings for Q4 2025.
Investment Quick Answers
What is CUSIP 55287L101?
CUSIP 55287L101 identifies MBX - MBX Biosciences, Inc. - COMMON STOCK in SEC 13F datasets.
Where can I see the latest institutional holders?
Review the Q4 2025 holders report and the ownership history table below.
Next ownership checks
Use the next link that matches the question you still need to answer about this security.
- Latest 13F filings when you want to inspect fresh institutional portfolio moves.
- Latest Schedule 13D/13G reports when you need large-owner changes outside the 13F cycle.
- All institutional ownership pages to compare this security with other holder-history pages.
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 55287L101:
Significant Owners of MBX Biosciences, Inc. - COMMON STOCK (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 |
| ORBIMED ADVISORS LLC | 7.7% | -14% | $118,413,222 | -$11,880,750 | 3,637,887 | -9.1% | ORBIMED ADVISORS LLC | 05 Feb 2026 |
| New Enterprise Associates 17, L.P. | 8.1% | $63,340,795 | 3,619,474 | Edward T. Mathers | 06 Nov 2025 | |||
| WELLINGTON MANAGEMENT GROUP LLP | 7.5% | -30% | $109,041,231 | -$47,958,356 | 3,349,961 | -31% | Wellington Management Group LLP | 31 Dec 2025 |
| FMR LLC | 6.2% | $87,660,017 | 2,936,684 | FMR LLC | 31 Mar 2026 | |||
| BlackRock, Inc. | 4.8% | -6% | $68,281,785 | +$487,630 | 2,287,497 | +0.72% | BlackRock, Inc. | 31 Mar 2026 |
| Deep Track Capital, LP | 6.6% | $28,604,897 | 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 31 Dec 2025, 136 institutional investors reported holding 48,426,905 shares of MBX Biosciences, Inc. - COMMON STOCK (MBX). This represents 102% of the company’s total 47,365,871 outstanding shares.
Top 25 Institutional Shareholders
The largest institutional shareholders of MBX Biosciences, Inc. - COMMON STOCK (MBX) together control 91% 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 | 0% | 5.6% | $209,804,490 |
| ORBIMED ADVISORS LLC | 8.3% | 3,935,203 | -1.7% | 2.7% | $124,116,303 |
| NEA Management Company, LLC | 7.6% | 3,614,486 | 0% | 5.8% | $114,000,888 |
| WELLINGTON MANAGEMENT GROUP LLP | 7.1% | 3,349,961 | -31% | 0.02% | $105,657,771 |
| Deep Track Capital, LP | 6.9% | 3,249,790 | +3.2% | 2.3% | $102,498,377 |
| BlackRock, Inc. | 6.2% | 2,919,756 | +49% | 0% | $92,089,105 |
| NVP ASSOCIATES, LLC | 4.5% | 2,136,335 | 0% | 26% | $67,380,006 |
| EcoR1 Capital, LLC | 4.5% | 2,123,604 | 0% | 3.1% | $66,978,470 |
| VANGUARD GROUP INC | 3.8% | 1,817,811 | +8.4% | 0% | $57,333,759 |
| Driehaus Capital Management LLC | 3% | 1,408,159 | -8.5% | 0.3% | $44,413,335 |
| Cormorant Asset Management, LP | 2.4% | 1,120,000 | -8.6% | 2% | $35,324,800 |
| BRAIDWELL LP | 2.2% | 1,018,600 | 1% | $32,126,644 | |
| Woodline Partners LP | 2.1% | 1,000,063 | -17% | 0.12% | $31,541,987 |
| Kynam Capital Management, LP | 2% | 934,799 | -53% | 1.9% | $29,483,560 |
| EVENTIDE ASSET MANAGEMENT, LLC | 1.9% | 890,000 | 0.44% | $28,070,600 | |
| Parkman Healthcare Partners LLC | 1.9% | 885,639 | +15% | 2.7% | $27,933,054 |
| PRICE T ROWE ASSOCIATES INC /MD/ | 1.8% | 840,506 | -12% | 0% | $26,511,000 |
| CITADEL ADVISORS LLC | 1.7% | 809,857 | -19% | 0.02% | $25,542,890 |
| Point72 Asset Management, L.P. | 1.4% | 680,609 | +8.4% | 0.03% | $21,466,408 |
| STATE STREET CORP | 1.4% | 672,740 | +111% | 0% | $21,218,220 |
| D. E. Shaw & Co., Inc. | 1.4% | 671,838 | 0.02% | $21,189,771 | |
| TCG Crossover Management, LLC | 1.4% | 650,000 | 0% | 0.68% | $20,501,000 |
| GEODE CAPITAL MANAGEMENT, LLC | 1.4% | 649,391 | +37% | 0% | $20,486,608 |
| MILLENNIUM MANAGEMENT LLC | 0.98% | 462,049 | -30% | 0.01% | $14,573,025 |
| Soleus Capital Management, L.P. | 0.86% | 408,900 | +49% | 0.55% | $12,896,706 |
Institutional Holders of MBX Biosciences, Inc. - COMMON STOCK (MBX) across Reporting Periods
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 4,428,044 | $132,176,887 | +$46,282,646 | $29.85 | 49 |
| 2025 Q4 | 48,426,905 | $1,527,200,912 | +$34,719,624 | $31.54 | 136 |
| 2025 Q3 | 47,790,065 | $836,364,494 | +$203,956,820 | $17.50 | 117 |
| 2025 Q2 | 36,839,365 | $420,338,016 | +$15,667,999 | $11.41 | 87 |
| 2025 Q1 | 35,666,401 | $263,219,997 | +$14,436,597 | $7.38 | 79 |
| 2024 Q4 | 32,941,714 | $606,485,118 | +$45,787,522 | $18.43 | 63 |
| 2024 Q3 | 30,305,441 | $784,071,713 | +$784,024,689 | $25.98 | 45 |