MBX Biosciences, Inc. (MBX)

Nasdaq: MBX · Pharmaceutical Preparations · Carmel, IN · filing with the SEC since 2019

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Grade4.5

◀ Past 4.3● Present 4.4▶ Future 4.6

6 est.

Overview Business Financials Grade Forecast Sentiment Ownership People Filings Patents Chart

Who owns MBX Biosciences, Inc.

As filed with the SEC

Holders of 5% or more

James N. Topper holds 11.7% of Common Stock, $0.0001 par value per share, as its SCHEDULE 13D/A filed Aug 10, 2026 says.

Directors and officers

report now, of 17 people on the record since 2024. Their holdings as a group are not read here.

Institutions as a whole

n/a

The record does not read the share held by managers that file Form 13F, so none is printed and no split of the rest is estimated. What it holds is the 7 named at left.

Holders of 5% or moreshare of the class, as filed

James N. Topper

SCHEDULE 13D/A · filed Aug 10, 2026 · Common Stock, $0.0001 par value per share · 11.7% in Sep 30, 2025

11.7%

Fmr LLC

SCHEDULE 13G/A · filed Jul 8, 2026 · COMMON STOCK · 6.2% in May 6, 2026

11.2%

Wellington Management Group LLP

SCHEDULE 13G/A · filed Jul 8, 2026 · Common Stock · 7.5% in Feb 10, 2026

10.5%

New Enterprise Associates 17, L.P.

SCHEDULE 13D/A · filed Nov 10, 2025 · Common Stock, par value $0.0001 per share

8.1%

Orbimed Advisors LLC

SCHEDULE 13D/A · filed Aug 10, 2026 · COMMON STOCK · 7.7% in Feb 11, 2026

6.4%

Blackrock, Inc.

SCHEDULE 13G · filed Jul 29, 2026 · Common Stock · 4.8% in Apr 27, 2026

5.5%

Paradigm BioCapital Advisors LP

SCHEDULE 13G · filed Jun 24, 2026 · Common Stock, $0.0001 par value per share

5.2%

Norwest Venture Partners XVI, LP

SCHEDULE 13D/A · filed Sep 30, 2025 · Common Stock, $0.0001 par value per share · reported falling below 5%

under 5%

Wellington Biomedical Innovation Master Investors (Cayman) II, L.P.

SCHEDULE 13G/A · filed Nov 12, 2025 · Common Stock · reported falling below 5%

under 5%

P. Kent Hawryluk

SCHEDULE 13G/A · filed Nov 14, 2025 · Common Stock, par value $0.0001 per share · reported falling below 5%

under 5%

Deep Track Capital, LP

SCHEDULE 13G/A · filed Aug 14, 2026 · Common Stock, $0.0001 par value per share · reported falling below 5%, from 6.55% in Aug 14, 2025

under 5%

What MBX reports owning in othersstakes of 5% or more, and other ties

MBX Biosciences, Inc. reports no stake in another company in the record.

Insider tradesForm 4

7sales

1purchases

2sales on a scheduled plan

3people selling

$3.0Msold, in dollars

$500,000bought, in dollars

Open-market trades on Form 4 from Nov 12, 2025 to Nov 12, 2026. A scheduled plan is a selling program set in advance under SEC rule 10b5-1. The trades are listed as filed and do not feed the grade.

By calendar yearSoldBought

242526

2026 runs to Nov 12, 2026. Dollars as filed, summed by the transaction date.

People who traded in the window3 of 33 on the roster

Person	Role as filed	Sales	Sold	On a plan	Buys	Bought
Azoulay Salomon	Chief Medical Officer	5	$2.7M	2	0	$0
Hoerter Steven L.	Chairman, President and CEO	1	$300,000	0	0	$0
Hawryluk P. Kent	President & CEO	1	$0	0	1	$500,000

SI Assistanton MBX · research, not advice