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MBX Biosciences, Inc.

MBX
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001776111

In the last 90 days, MBX Biosciences, Inc. insiders filed 0 open-market purchases and 1 sale; 172 institutions reported holding it in 13F filings for Q2 2026, worth $3.06B in total; no superinvestor holds it.

Holders of 5% or more of MBX

Holders whose latest Schedule 13D or 13G filing reports 5% or more of MBX Biosciences, Inc., largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of MBX
HolderLatest formStakeChangeFirst filedLatest filingFiling
Frazier Life Sciences Public Fund, L.P.13D/A11.70%5.22M shares−1.90 ppfrom 13.60%Aug 20, 20252 filingsSep 30, 2025SEC
New Enterprise Associates 17, L.P.13D/A8.10%3.62M shares–Nov 10, 20251 filingNov 10, 2025SEC
OrbiMed Advisors LLC13D/A7.70%3.64M shares−1.30 ppfrom 9.00%Sep 30, 20252 filingsFeb 11, 2026SEC
Wellington Management Group LLP13G/A7.50%3.35M shares−3.30 ppfrom 10.80%May 12, 20254 filingsFeb 10, 2026SEC
Deep Track Capital, LP13G/A6.55%2.19M shares–Aug 14, 20251 filingAug 14, 2025SEC
Paradigm Biocapital Advisors LP13G5.20%2.49M sharesNewJun 24, 20261 filingJun 24, 2026SEC
BlackRock, Inc.13G5.10%2.27M sharesNewJan 21, 20261 filingJan 21, 2026SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

15 Schedule 13D and 13G filings on MBX Biosciences, Inc., newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on MBX
Filed (ET)FilerFormStakeChangeEvent dateFiling
Jun 24, 20264:05 PM ETParadigm Biocapital Advisors LPand 3 others13G5.20%2.49M sharesNewJun 16, 2026SEC
Feb 11, 20266:42 PM ETOrbiMed Advisors LLCand 2 others13D/A7.70%3.64M shares−1.30 ppfrom 9.00%Feb 5, 2026SEC
Feb 10, 202611:21 AM ETWellington Management Group LLPand 3 others13G/A7.50%3.35M shares−3.30 ppfrom 10.80%Dec 31, 2025SEC
Jan 21, 202612:30 PM ETBlackRock, Inc.13G5.10%2.27M sharesNewDec 31, 2025SEC
Nov 14, 20254:05 PM ETHawryluk P. Kent13G/A4.30%2.00M shares–Below 5%Sep 30, 2025SEC
Nov 12, 20256:44 PM ETWellington Biomedical Innovation Master Investors (Cayman) II L.P.13G/A4.50%2.02M shares–Below 5%Sep 30, 2025SEC
Nov 10, 20255:08 PM ETNew Enterprise Associates 17, L.P.and 11 others13D/A8.10%3.62M shares–Nov 6, 2025SEC
Oct 6, 202512:22 PM ETWellington Management Group LLPand 3 others13G/A10.80%4.82M shares+4.00 ppfrom 6.80%Sep 30, 2025SEC
Sep 30, 20257:06 PM ETOrbiMed Advisors LLCand 2 others13D/A9.00%4.00M shares–Sep 26, 2025SEC
Sep 30, 20256:15 PM ETNorwest Venture Partners XVI, LPand 5 others13D/A4.80%2.14M shares–Below 5%Sep 26, 2025SEC
Sep 30, 20255:01 PM ETFrazier Life Sciences Public Fund, L.P.and 13 others13D/A11.70%5.22M shares−1.90 ppfrom 13.60%Sep 26, 2025SEC
Aug 20, 20255:23 PM ETFrazier Life Sciences Public Fund, L.P.and 16 others13D/A13.60%4.56M shares–Aug 18, 2025SEC
Aug 14, 20258:48 AM ETDeep Track Capital, LPand 2 others13G/A6.55%2.19M shares–Jun 30, 2025SEC
Aug 12, 202510:34 AM ETWellington Management Group LLPand 3 others13G/A6.80%2.27M shares−1.10 ppfrom 7.90%Jun 30, 2025SEC
May 12, 202510:44 AM ETWellington Management Group LLPand 3 others13G/A7.90%2.64M shares–Mar 31, 2025SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell MBX Biosciences, Inc. shares.

No Form 144 notices for MBX Biosciences, Inc. are on file.