DOSSIER · 13F Holders · Q3 2026

MBX BIOSCIENCES INC

3 institutions still hold MBX BIOSCIENCES INC as of Q3 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 55287L901·3 13F holders·last filed Sep 30, 2026
Market cap
—
13F value held
$41K
visible holders
Holders
3
filers reporting
Concentration
57.14%
GROUP ONE TRADING LLC #1
top holder share
AI Holders Summary · Q3 2026

3 institutions reported MBX BIOSCIENCES INC in Q3 2026. GROUP ONE TRADING LLC leads at 57.1% of the visible book.

Top holders

Sorted by position value. Source: SEC EDGAR 13F-HR filings.

#HolderValueShares% port.Quarter
01
GROUP ONE TRADING LLC
CIK 0000932540
$23K4000.00%Q3 2026
02
SIMPLEX TRADING, LLC
CIK 0001488542
$18K3000.00%Q3 2026
03
CONCOURSE FINANCIAL GROUP SECURITIES, INC.
CIK 0000752798
$00—Q2 2025