DOSSIER · 13F Holders · Q1 2026Technology · Services-Business Services, NECMega-capCrowded
MAX

MEDIAALPHA INC

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

CUSIP 58450V104·Services-Business Services, NEC·170 13F holders·last filed Mar 31, 2026
Market cap
5.5%
vs prior quarter
13F value held
$358M
59.0% inst. owned
of float
Holders
170
-107 QoQ
filers reporting
Activity
+33 / −87
+822 added · −846 reduced
this quarter
Concentration
46.33%
WHITE MOUNTAINS INSURANCE GROUP LTD #1
top holder share
AI Holders Summary · Q1 2026

170 institutions reported MAX in Q1 2026. WHITE MOUNTAINS INSURANCE GROUP LTD leads at 46.3% of the visible book. -107 net institutions QoQ — distribution reading.

Top holders

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

#HolderValueShares% port.Quarter
01
WHITE MOUNTAINS INSURANCE GROUP LTD
CIK 0000776867
$166M17.9M52.99%Q1 2026
02
BlackRock, Inc.
CIK 0002012383
$32M3.5M0.00%Q1 2026
03
J. Goldman & Co LP
CIK 0001412741
$17M1.9M0.51%Q1 2026
04
Clearline Capital LP
CIK 0001600136
$17M1.3M0.83%Q4 2025
05
JPMORGAN CHASE & CO
CIK 0000019617
$16M1.7M0.00%Q1 2026
06
VANGUARD CAPITAL MANAGEMENT LLC
CIK 0002100119· Index
$13M1.4M0.00%Q1 2026
07
GEODE CAPITAL MANAGEMENT, LLC
CIK 0001214717· Index
$10M1.1M0.00%Q1 2026
08
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP
CIK 0001164508
$10M1.1M0.01%Q1 2026
09
JACOBS ASSET MANAGEMENT, LLC
CIK 0001351063
$9M924K5.15%Q1 2026
10
STATE STREET CORP
CIK 0000093751
$8M838K0.00%Q1 2026
11
Shay Capital LLC
CIK 0001723643
$7M775K0.60%Q1 2026
12
JACOBS LEVY EQUITY MANAGEMENT, INC
CIK 0000884414
$7M750K0.03%Q1 2026
13
RENAISSANCE TECHNOLOGIES LLC
CIK 0001037389
$7M719K0.01%Q1 2026
14
MORGAN STANLEY
CIK 0000895421
$7M703K0.00%Q1 2026
15
Nuveen, LLC
CIK 0001871926
$7M701K0.00%Q1 2026
16
GOLDMAN SACHS GROUP INC
CIK 0000886982
$6M623K0.00%Q1 2026
17
DIMENSIONAL FUND ADVISORS LP
CIK 0000354204· Quasi-passive
$6M621K0.00%Q1 2026
18
D. E. Shaw & Co., Inc.
CIK 0001009207
$5M397K0.00%Q4 2025
19
Vanguard Portfolio Management
CIK 0002100121
$5M547K0.00%Q1 2026
20
AQR CAPITAL MANAGEMENT LLC
CIK 0001167557
$4M482K0.00%Q1 2026
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