13F

Stock

Seres Therapeutics, Inc.

MCRB · held by 33 managers

Reported value

$20.5M

Holders

33

+2 new · −8 exited

Holders’ est. mark

−$11.2M

Price effect on 28 books still in the name

Largest holder

$10.3M

Flagship Pioneering, LLC

Notable conviction

Share of each notable manager’s 13F book.

Holder count by quarter

Who holds it

Notable only
InvestorSharesValueEst. markChange
Flagship Pioneering, LLC1.16M$10.3M−$6.98MCut−$6.98M
VANGUARD CAPITAL MANAGEMENT LLC294.1K$2.61MHeld
MARSHALL WACE, LLP139.5K$1.24M−$722.3KCut−$550.5K
Vontobel Holding Ltd.138.5K$1.23M−$620.4KCut−$307.9K
SUSQUEHANNA INTERNATIONAL GROUP, LLP105.3K$934.4K−$633.1KCut−$1.74M
BlackRock, Inc.102K$905K−$613.2KCut−$636.9K
GEODE CAPITAL MANAGEMENT, LLC74.8K$664.1K−$449.9KCut−$618.2K
AMERICAN CENTURY COMPANIES INC62.3K$552.7K−$97.8KAdded$310.6K
VANGUARD FIDUCIARY TRUST CO39.6K$351.6KHeld
State Street33.9K$300.7K−$203.7KCut−$203.7K
CHARLES SCHWAB INVESTMENT MANAGEMENT INC31.6K$280.6K−$188.5KCut−$186.2K
Lion Point Capital, LP31.6K$280K−$189.7KCut−$189.7K
MORGAN STANLEY21.7K$192.5K−$130.4KCut−$181.4K
TWO SIGMA INVESTMENTS, LP18.8K$166.7K−$113KCut−$216.4K
NORTHERN TRUST CORP14.8K$131K−$88.7KCut−$88.7K
Invesco Ltd.14.5K$129K−$86.3KCut−$84.6K
UBS Group AG7.03K$62.4K−$25.4KCut−$526
BARCLAYS PLC6.51K$57.7K−$39.1KCut−$52.9K
SBI Securities Co., Ltd.3.48K$30.9K−$20.9KCut−$20.9K
SIMPLEX TRADING, LLC3.07K$27.2K−$7.4KAdded$8.9K
Vanguard Global Advisers, LLC1.98K$17.5KHeld
Fidelity1.75K$15.5K−$10.5KCut−$10.4K
Rachor Investment Advisory Services, LLC1.48K$13.1K−$8.88KCut−$8.88K
GROUP ONE TRADING LLC824$7.31KNew
Tower Research Capital LLC (TRC)794$7.04KNew
BNP PARIBAS FINANCIAL MARKETS211$1.87K−$1.27KCut−$9.63K
Physician Wealth Advisors, Inc.142$1.26K−$853Cut−$853
ROYAL BANK OF CANADA107$1K$84Added$1K
WELLS FARGO & COMPANY/MN10$89−$60Cut−$3.78K
Sound Income Strategies, LLC8$71−$57Cut−$57
OSAIC HOLDINGS, INC.8$70−$49Cut−$49
Allworth Financial LP4$36−$24Cut−$24
Arax Advisory Partners6$18−$24Cut−$12

Who left

Positions as of Q1 2026. 13F filings arrive up to 45 days after quarter-end and omit shorts. Values are quarter-end marks, as filed. Estimated mark is the price effect on shares still held — not realized P&L or investment advice.