DOSSIER · 13F Holders · Q1 2026

PROTAGONIST THERAPEUTICS INC

3 institutions still hold PROTAGONIST THERAPEUTICS INC as of Q1 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 74366E902·3 13F holders·last filed Mar 31, 2026
Market cap
13F value held
$6M
visible holders
Holders
3
filers reporting
Concentration
65.19%
SIMPLEX TRADING, LLC #1
top holder share
AI Holders Summary · Q1 2026

3 institutions reported PROTAGONIST THERAPEUTICS INC in Q1 2026. SIMPLEX TRADING, LLC leads at 65.2% of the visible book.

Top holders

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

#HolderValueShares% port.Quarter
01
SIMPLEX TRADING, LLC
CIK 0001488542
$4M35K0.00%Q1 2026
02
GROUP ONE TRADING LLC
CIK 0000932540
$2M19K0.00%Q1 2026
03
CONCOURSE FINANCIAL GROUP SECURITIES, INC.
CIK 0000752798
$00Q2 2025