Security key
55287L101
MBX Biosciences, Inc. - Common Stock, $0.0001 par value per share (MBX)
CUSIP: 55287L101
Q4 2025 13F Holders as of 31 Dec 2025
- Security type / class
- Equity / Common Stock, $0.0001 par value per share
- Total 13F shares
- 48,428,720
- Total 13F value
- $1,527,258,385
- Share change
- -32,951
- Put/Call ratio
- 365%
- SEC-reported price per share
- $31.54
- Number of holders
- 138
- Value change
- +$34,720,034
- Number of buys
- 91
- Number of sells
- 50
- Shares outstanding
- 47,598,049
Holder snapshot
7 signals
Open additional details 1 more signal available
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q4 2025
Institutions
138
Top holders
10
MBX full security history
Ownership snapshot
Full 13F holder table
MBX Biosciences, Inc. SEC filings
MBX Biosciences, Inc. company facts
Broader feeds
Ownership snapshot
Top reported holders of MBX - MBX Biosciences, Inc. - Common Stock, $0.0001 par value per share (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
New Enterprise Associates...
Disclosed value leader
Frazier Life Sciences Man...
Comparable rows
15/15
Latest evidence
06 Nov 2025
13D/G
3/4/5
13F
Lead comparable stake: 8.1%
13D/G row: New Enterprise Associates 17, L.P.
Showing 1-6 of 15 holder rows.
Quick read
New Enterprise Associates 17, L.P. leads the comparable SEC ownership view at 8.1%.
15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens New Enterprise Associates 17, L.P.'s linked filing trail.
Comparable ownership
Top 5
New Enterprise Associates 17, L.P.
8.1%
Norwest Venture Partners XVI, LP
4.8%
Wellington Biomedical Innovation ...
4.5%
P. Kent Hawryluk
4.3%
Frazier Life Sciences Management,...
14%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| New Enterprise Associates 17, L.P. |
13D/G
3/4/5
Edward T. Mathers · 10%+ Owner
|
8.1%
|
$63,340,795
3,619,474 shares
|
$0 | 06 Nov 2025 |
| Norwest Venture Partners XVI, LP |
13D/G
Tiba Aynechi
|
4.8%
|
$29,738,337
2,140,989 shares
|
$0 | 26 Sep 2025 |
| Wellington Biomedical Innovation Master Investors (Cayman) II L.P. |
13D/G
3/4/5
10%+ Owner
|
4.5%
|
$35,304,395
2,017,394 shares
|
$0 | 30 Sep 2025 |
| P. Kent Hawryluk |
13D/G
|
4.3%
|
$34,925,782
1,995,759 shares
|
$0 | 30 Sep 2025 |
| Frazier Life Sciences Management, L.P. |
13F
Company
|
14%
|
$116,410,228
6,652,013 shares
|
— | 30 Sep 2025 |
| WELLINGTON MANAGEMENT GROUP LLP |
13F
Company
|
10%
|
$84,408,382
4,823,336 shares
|
— | 30 Sep 2025 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q4 2025
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
138
Shares
48,428,720
Rows available
138
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q4 2025 vs Q3 2025 Across Filers
Q3 2025 holders
117
Q4 2025 holders
138
Holder diff
21
| Investor | Q3 2025 Shares | Q4 2025 Shares | Share Diff | Share Chg % | Q3 2025 value | Q4 2025 value | Value change | Value Chg % |
|---|