DOSSIER · 13F Holders · Q2 2026

SELLAS LIFE SCIENCES GROUP I

4 institutions still hold SELLAS LIFE SCIENCES GROUP I as of Q2 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 81642T909·4 13F holders·last filed Jun 30, 2026
Market cap
13F value held
$117M
visible holders
Holders
4
filers reporting
Concentration
84.02%
GROUP ONE TRADING LLC #1
top holder share
AI Holders Summary · Q2 2026

4 institutions reported SELLAS LIFE SCIENCES GROUP I in Q2 2026. GROUP ONE TRADING LLC leads at 84.0% 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
$98M6.6M0.14%Q2 2026
02
SIMPLEX TRADING, LLC
CIK 0001488542
$17M1.2M0.01%Q2 2026
03
Marathon Trading Investment Management LLC
CIK 0001572748
$1M95K0.04%Q2 2026
04
CONCOURSE FINANCIAL GROUP SECURITIES, INC.
CIK 0000752798
$00Q2 2025