DOSSIER · 13F Holders · Q4 2025Defensive growthQuality
MCRB

SERES THERAPEUTICS INC

36 institutions still hold SERES THERAPEUTICS INC as of Q4 2025. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 81750R201·36 13F holders·last filed Dec 31, 2025
Market cap
0.5%
vs prior quarter
13F value held
$31M
58.0% inst. owned
of float
Holders
36
+119 QoQ
filers reporting
Activity
+104 / −75
+977 added · −800 reduced
this quarter
Concentration
55.41%
Flagship Pioneering Inc. #1
top holder share
AI Holders Summary · Q4 2025

36 institutions reported MCRB in Q4 2025. Flagship Pioneering Inc. leads at 55.4% of the visible book. +119 net new institutions vs prior quarter — accumulation reading.

Top holders

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

#HolderValueShares% port.Quarter
01
Flagship Pioneering Inc.
CIK 0001400240
$17M1.2M5.32%Q4 2025
02
VANGUARD CAPITAL MANAGEMENT LLC
CIK 0002100119· Index
$3M294K0.00%Q1 2026
03
SUSQUEHANNA INTERNATIONAL GROUP, LLP
CIK 0001446194· Market maker
$2M227K0.00%Q1 2026
04
MARSHALL WACE, LLP
CIK 0001318757
$2M120K0.00%Q4 2025
05
Vontobel Holding Ltd.
CIK 0001588340
$1M138K0.00%Q1 2026
06
CITADEL ADVISORS LLC
CIK 0001423053
$1M74K0.00%Q4 2025
07
BlackRock, Inc.
CIK 0002012383
$904,970102K0.00%Q1 2026
08
683 Capital Management, LLC
CIK 0001404574
$778,43252K0.03%Q4 2025
09
GEODE CAPITAL MANAGEMENT, LLC
CIK 0001214717· Index
$664,10875K0.00%Q1 2026
10
AMERICAN CENTURY COMPANIES INC
CIK 0000748054
$552,74362K0.00%Q1 2026
11
VANGUARD FIDUCIARY TRUST CO
CIK 0000933478· Index
$351,63340K0.00%Q1 2026
12
HAP TRADING, LLC
CIK 0001049854
$334,750125K0.02%Q3 2025
13
STATE STREET CORP
CIK 0000093751
$300,70234K0.00%Q1 2026
14
CHARLES SCHWAB INVESTMENT MANAGEMENT INC
CIK 0000884546· Index
$280,55832K0.00%Q1 2026
15
Lion Point Capital, LP
CIK 0001643354
$280,02632K1.67%Q1 2026
16
MORGAN STANLEY
CIK 0000895421
$192,47822K0.00%Q1 2026
17
TWO SIGMA INVESTMENTS, LP
CIK 0001179392
$166,70319K0.00%Q1 2026
18
NORTHERN TRUST CORP
CIK 0000073124· Index
$130,96615K0.00%Q1 2026
19
Invesco Ltd.
CIK 0000914208
$129,03215K0.00%Q1 2026
20
UBS Group AG
CIK 0001610520
$62,3577K0.00%Q1 2026
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