DOSSIER · 13F Holders · Q2 2026

BANCO SANTANDER S.A.

5 institutions still hold BANCO SANTANDER S.A. as of Q2 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 05964H955·5 13F holders·last filed Jun 30, 2026
Market cap
13F value held
$3M
visible holders
Holders
5
filers reporting
Concentration
38.41%
SIMPLEX TRADING, LLC #1
top holder share
AI Holders Summary · Q2 2026

5 institutions reported BANCO SANTANDER S.A. in Q2 2026. SIMPLEX TRADING, LLC leads at 38.4% 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
$1M94K0.00%Q2 2026
02
Optiver Holding B.V.
CIK 0001859606· Market maker
$1M73K0.00%Q2 2026
03
GROUP ONE TRADING LLC
CIK 0000932540
$684K50K0.00%Q2 2026
04
IMC-Chicago, LLC
CIK 0001452861· Market maker
$381K28K0.00%Q2 2026
05
CONCOURSE FINANCIAL GROUP SECURITIES, INC.
CIK 0000752798
$00Q2 2025