13F Insight
DOSSIER · 13F Holders · Q3 2026

BLOCK INC

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

CUSIP 852234953·12 13F holders·last filed Sep 30, 2026
Market cap
—
13F value held
$241M
visible holders
Holders
12
filers reporting
Concentration
35.45%
IMC-Chicago, LLC #1
top holder share
AI Holders Summary · Q3 2026

12 institutions reported BLOCK INC in Q3 2026. IMC-Chicago, LLC leads at 35.5% of the visible book.

Top holders

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

#HolderValueShares% port.Quarter
01
IMC-Chicago, LLC
CIK 0001452861· Market maker
$85M1.2M0.02%Q3 202602
Optiver Holding B.V.
CIK 0001859606· Market maker
$79M1.0M0.02%Q2 202603
Capital Markets Trading UK LLP
CIK 0001719165
$24M403K0.30%Q1 202604
SIMPLEX TRADING, LLC
CIK 0001488542
$17M225K0.01%Q3 202605
NATIONAL BANK OF CANADA /FI/
CIK 0000926171
$11M1K0.01%Q2 202606
Maven Securities LTD
CIK 0001633046
$8M101K0.15%Q2 202607
HRT FINANCIAL LP
CIK 0001475597
$5M75K0.02%Q4 202508
GROUP ONE TRADING LLC
CIK 0000932540
$5M64K0.01%Q2 202609
JPMORGAN CHASE & CO
CIK 0000019617
$4M50K0.00%Q2 202610
CMT Capital Markets Trading GmbH
CIK 0001632813
$3M55K0.03%Q1 202611
SG Americas Securities, LLC
CIK 0001313360
$130K28K0.00%Q1 202612
CONCOURSE FINANCIAL GROUP SECURITIES, INC.
CIK 0000752798
$00—Q2 2025