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IGM Biosciences, Inc. (IGMS) institutional ownership

Market cap$81M SectorHealthcare
Funds holding · Q4 2025
2
reported IGMS position changes
Top owners · Q1 2026
No disclosed owners are available.
Institutional activity · Q4 2025
Activity unavailable N/A
0 buyers · 2 sellers

IGM Biosciences, Inc. (IGMS) price and institutional activity

Dates

Q4 2025

$0 bought by 0 investors
$0 sold by 2 investors
Barclays PLCOsaic Holdings, Inc.
Bought Sold Totals per quarter; hover a bar for the names.

IGM Biosciences, Inc. (IGMS) institutional activity · 2

Investor Type Est. change Change Δ Own Date
Barclays PLC · Exited
Change −22K Δ Own −100.0% Date Q4 2025
Barclays PLC Exited· Q4 2025 −22K −100.0% Q4 2025
Osaic Holdings, Inc. · Exited
Change −400 Δ Own −100.0% Date Q4 2025
Osaic Holdings, Inc. Exited· Q4 2025 −400 −100.0% Q4 2025
Data through Q4 2025 · filed Mar 19, 2026
2 of 2

Famous investor activity in IGM Biosciences, Inc. (IGMS)

IGM Biosciences, Inc. (IGMS) insider trading

Company insiders, action and economics first; trade and filed dates last.
Dates
Insider Title Type Price Qty Value Owned ΔOwn Trade date Filed date
Baker Bros. Advisors LP · Other 4 operations -14.8M
Owned 0 Trade date Aug 14, 2025 Filed date Aug 18, 2025
Baker Bros. Advisors LP Other 4 operations -14.8M 0 Aug 14, 2025 Aug 18, 2025
Green Jeremy · 10% Owner 3 operations -10.8M
Owned 0 Trade date Aug 14, 2025 Filed date Aug 15, 2025
Green Jeremy 10% Owner 3 operations -10.8M 0 Aug 14, 2025 Aug 15, 2025
Hambleton Julie · Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -2K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Hambleton Julie Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -2K 0 Aug 14, 2025 Aug 14, 2025
Lee Michael Stewart · Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -13K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Lee Michael Stewart Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -13K 0 Aug 14, 2025 Aug 14, 2025
Topsoe Holding A/s · 10% Owner 2 operations -15.4M
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Topsoe Holding A/s 10% Owner 2 operations -15.4M 0 Aug 14, 2025 Aug 14, 2025
Topsoe Jakob Haldor · Director, 10% Owner 3 operations -15.5M
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Topsoe Jakob Haldor Director, 10% Owner 3 operations -15.5M 0 Aug 14, 2025 Aug 14, 2025
Topsoe Christina Teng · Director, 10% Owner 4 operations -15.5M
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Topsoe Christina Teng Director, 10% Owner 4 operations -15.5M 0 Aug 14, 2025 Aug 14, 2025
Thompson Elizabeth H.z. · Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -7K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Thompson Elizabeth H.z. Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -7K 0 Aug 14, 2025 Aug 14, 2025
Strohl William · Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -125K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Strohl William Director Shares transferred outside the market (D), often for tax or as a gift, not a market sale -125K 0 Aug 14, 2025 Aug 14, 2025
Harler Mary Beth · Director, Officer Shares transferred outside the market (D), often for tax or as a gift, not a market sale -324K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Harler Mary Beth Director, Officer Shares transferred outside the market (D), often for tax or as a gift, not a market sale -324K 0 Aug 14, 2025 Aug 14, 2025
Behrens M. Kathleen · Director 4 operations -413K
Owned 0 Trade date Aug 14, 2025 Filed date Aug 14, 2025
Behrens M. Kathleen Director 4 operations -413K 0 Aug 14, 2025 Aug 14, 2025
11 of 11

IGM Biosciences, Inc. (IGMS) activist and large shareholders

Dates
Owner/Filer identity Shares reported % of shares outstanding Filing date
Topsoe Holding A 10.4M
% of shares outstanding 31.8% Filing date Jul 19, 2023
Topsoe Holding A 10.4M 31.8% Jul 19, 2023
Baker Bros. Advisors LP 4.1M
% of shares outstanding 12.4% Filing date Mar 28, 2024
Baker Bros. Advisors LP 4.1M 12.4% Mar 28, 2024
T. Rowe Price Associates, Inc. 3.6M
% of shares outstanding 10.5% Filing date Feb 14, 2025
T. Rowe Price Associates, Inc. 3.6M 10.5% Feb 14, 2025
Invus Global Management, LLC 3.3M
% of shares outstanding 9.9% Filing date Aug 2, 2024
Invus Global Management, LLC 3.3M 9.9% Aug 2, 2024
Redmile Group, LLC 3.3M
% of shares outstanding 9.9% Filing date Jun 28, 2023
Redmile Group, LLC 3.3M 9.9% Jun 28, 2023
Artal International S.c.a. 3.1M
% of shares outstanding 9.4% Filing date Feb 9, 2024
Artal International S.c.a. 3.1M 9.4% Feb 9, 2024
FMR LLC 820K
% of shares outstanding 2.4% Filing date Nov 12, 2024
FMR LLC 820K 2.4% Nov 12, 2024
Glazer Capital, LLC 0
% of shares outstanding 0.0% Filing date Nov 13, 2025
Glazer Capital, LLC 0 0.0% Nov 13, 2025
8 of 8

IGM Biosciences, Inc. (IGMS) ownership FAQ

Who owns IGMS?

2 reporting institutions disclosed IGMS position changes in the Q4 2025 snapshot.

How is institutional activity calculated?

For each manager, WhoBought compares accepted consecutive 13F share counts. Share change is current shares minus prior shares. Estimated dollar change is that signed share change multiplied by the split-adjusted quarter-mean close. The activity table on this page uses Q4 2025.

What are activist and large shareholder filings?

An investor crossing 5% of a share class generally files Schedule 13D for activist intent or Schedule 13G for a passive position. The technical form names appear here rather than in the activity rows.

Where does this data come from?

Ownership and institutional activity come from SEC Form 13F filings. Insider activity comes from SEC Form 4, and large-shareholder activity from SEC Schedules 13D and 13G. FMP supplies price data only. Company logos use the local verified Parqet cache with one shared fallback.

Why are ownership reports delayed?

Form 13F is a quarterly disclosure and is normally filed after the quarter ends. Every ownership and activity value therefore names its represented period; it is not presented as a live position.

How are missing table values shown?

A muted dash marks a missing table value. It means the filing omitted the value, comparable data is unavailable, or no prior position exists for comparison.