Who owns IMSR (IMSR)
Which tracked institutional funds hold IMSR, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See IMSR company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
23 tracked funds added or opened IMSR while 21 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
IMSR’s largest tracked holder by dollar value, MILLENNIUM MANAGEMENT LLC, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes IMSR more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in IMSR divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 106 tracked filers holding IMSR, 61 increased or opened the position and 57 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in IMSR between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 8
- EXCHANGE TRADED CONCEPTS, LLC$13M
- VANGUARD CAPITAL MANAGEMENT LLC$8M
- Vennlight Capital Management, LP$3M
- BOOTHBAY FUND MANAGEMENT, LLC$2M
- Creek Drive Management Group LLC$2M
- VANGUARD FIDUCIARY TRUST CO$2M
Full exits 9
- VANGUARD GROUP INC$11M
- Senator Investment Group LP$5M
- HBK INVESTMENTS L P$3M
- Galaxy Group Investments LLC$3M
- JANE STREET GROUP, LLC$2M
- HIGHBRIDGE CAPITAL MANAGEMENT LLC$1M
Largest adds
- MILLENNIUM MANAGEMENT LLC$405M
- LMR Partners LLP$3M
- ARISTEIA CAPITAL, L.L.C.$1M
- Magnetar Financial LLC$1M
- RENAISSANCE TECHNOLOGIES LLC$1M
- TORONTO DOMINION BANK$1M
Largest trims
- BALYASNY ASSET MANAGEMENT L.P.$8M
- CANTOR FITZGERALD, L. P.$6M
- CITADEL ADVISORS LLC$5M
- MMCAP International Inc. SPC$4M
- Verition Fund Management LLC$2M
- Walleye Capital LLC$1M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| MILLENNIUM MANAGEMENT LLC added | 156,396 | $405M | 62.0% | 2026-Q1 |
| EXCHANGE TRADED CONCEPTS, LLC new | 2,091,161 | $13M | 1.9% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,303,452 | $8M | 1.2% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 1,277,258 | $8M | 1.2% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 1,214,777 | $7M | 1.1% | 2026-Q1 |
| BlackRock, Inc. added | 1,120,885 | $7M | 1.0% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 1,073,073 | $6M | 0.9% | 2026-Q1 |
| Alyeska Investment Group, L.P. | 722,000 | $4M | 0.7% | 2026-Q1 |
| LMR Partners LLP trimmed | 690,702 | $4M | 0.6% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 659,388 | $4M | 0.6% | 2026-Q1 |
| Vennlight Capital Management, LP added | 575,499 | $3M | 0.5% | 2026-Q1 |
| PEAK6 LLC | 1,186,146 | $3M | 0.5% | 2026-Q1 |
| WINTON GROUP Ltd trimmed | 496,300 | $3M | 0.5% | 2026-Q1 |
| UBS Group AG trimmed | 493,577 | $3M | 0.5% | 2026-Q1 |
| CANTOR FITZGERALD, L. P. added | 1,083,051 | $3M | 0.4% | 2026-Q1 |
| Hudson Bay Capital Management LP trimmed | 452,287 | $3M | 0.4% | 2026-Q1 |
| Verition Fund Management LLC trimmed | 444,958 | $3M | 0.4% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 407,900 | $2M | 0.4% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 396,238 | $2M | 0.4% | 2026-Q1 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 390,000 | $2M | 0.4% | 2026-Q1 |
| Caption Management, LLC added | 865,372 | $2M | 0.3% | 2026-Q1 |
| STATE STREET CORP added | 345,520 | $2M | 0.3% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 337,991 | $2M | 0.3% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 330,276 | $2M | 0.3% | 2026-Q1 |
| Creek Drive Management Group LLC new | 330,000 | $2M | 0.3% | 2026-Q1 |
| ARISTEIA CAPITAL, L.L.C. added | 735,393 | $2M | 0.3% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 300,407 | $2M | 0.3% | 2026-Q1 |
| MORGAN STANLEY trimmed | 285,549 | $2M | 0.3% | 2026-Q1 |
| Magnetar Financial LLC trimmed | 244,000 | $1M | 0.2% | 2026-Q1 |
| HITE Hedge Asset Management LLC added | 240,113 | $1M | 0.2% | 2026-Q1 |
| TORONTO DOMINION BANK added | 225,974 | $1M | 0.2% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 205,903 | $1M | 0.2% | 2026-Q1 |
| Squarepoint Ops LLC added | 173,209 | $1M | 0.2% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 132,750 | $797K | 0.1% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 124,537 | $748K | 0.1% | 2026-Q1 |
| Harraden Circle Investments, LLC | 122,000 | $733K | 0.1% | 2026-Q1 |
| Yorkville Advisors Global, LP new | 122,000 | $733K | 0.1% | 2026-Q1 |
| Shay Capital LLC trimmed | 118,086 | $709K | 0.1% | 2026-Q1 |
| COMMONWEALTH EQUITY SERVICES, LLC added | 100,131 | $601K | 0.1% | 2026-Q1 |
| Periscope Capital Inc. trimmed | 122,000 | $580K | 0.1% | 2026-Q1 |
| SONA ASSET MANAGEMENT (US) LLC trimmed | 85,566 | $514K | 0.1% | 2026-Q1 |
| Linden Advisors LP | 194,560 | $500K | 0.1% | 2026-Q1 |
| K2 PRINCIPAL FUND, L.P. new | 80,000 | $481K | 0.1% | 2026-Q1 |
| TIEMANN INVESTMENT ADVISORS, LLC | 75,995 | $456K | 0.1% | 2026-Q1 |
| Arosa Capital Management LP trimmed | 175,000 | $453K | 0.1% | 2026-Q1 |
| MOORE CAPITAL MANAGEMENT, LP added | 75,000 | $450K | 0.1% | 2026-Q1 |
| FNY Investment Advisers, LLC trimmed | 66,160 | $397K | 0.1% | 2026-Q1 |
| Massar Capital Management, LP | 65,000 | $390K | 0.1% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC new | 63,500 | $381K | 0.1% | 2026-Q1 |
| Walleye Capital LLC trimmed | 139,986 | $363K | 0.1% | 2026-Q1 |
| Diametric Capital, LP new | 59,191 | $355K | 0.1% | 2026-Q1 |
| Swiss National Bank new | 56,600 | $340K | 0.1% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 52,700 | $316K | 0.0% | 2026-Q1 |
| AQR Arbitrage LLC trimmed | 1,288,674 | $14M | 2.1% | 2025-Q1 stale |
| First Trust Capital Management L.P. trimmed | 1,051,124 | $12M | 1.8% | 2025-Q2 stale |
| VANGUARD GROUP INC new | 1,849,446 | $11M | 1.7% | 2025-Q4 stale |
| Encompass Capital Advisors LLC new | 946,165 | $10M | 1.5% | 2025-Q1 stale |
| Calamos Advisors LLC | 500,000 | $6M | 0.8% | 2025-Q2 stale |
| Senator Investment Group LP added | 900,000 | $5M | 0.8% | 2025-Q4 stale |
| COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS | 405,962 | $5M | 0.7% | 2025-Q2 stale |
| RIVERNORTH CAPITAL MANAGEMENT, LLC | 400,000 | $4M | 0.7% | 2025-Q2 stale |
| Sourcerock Group LLC new | 257,900 | $4M | 0.6% | 2025-Q3 stale |
| SIR Capital Management, L.P. new | 217,600 | $4M | 0.5% | 2025-Q3 stale |
| Governors Lane LP new | 300,000 | $3M | 0.5% | 2025-Q2 stale |
| Waratah Capital Advisors Ltd. new | 198,188 | $3M | 0.5% | 2025-Q3 stale |
| Galaxy Group Investments LLC added | 500,000 | $3M | 0.5% | 2025-Q4 stale |
| HBK INVESTMENTS L P new | 500,000 | $3M | 0.5% | 2025-Q4 stale |
| Polar Asset Management Partners Inc. trimmed | 257,307 | $3M | 0.4% | 2025-Q2 stale |
| BERKLEY W R CORP trimmed | 160,672 | $3M | 0.4% | 2025-Q3 stale |
| SCOGGIN MANAGEMENT LP new | 200,000 | $2M | 0.3% | 2025-Q2 stale |
| Westchester Capital Management, LLC trimmed | 199,691 | $2M | 0.3% | 2025-Q2 stale |
| Athos Capital Ltd new | 200,000 | $2M | 0.3% | 2025-Q1 stale |
| J. Goldman & Co LP new | 176,249 | $2M | 0.3% | 2025-Q2 stale |
| GRITSTONE ASSET MANAGEMENT LLC trimmed | 173,847 | $2M | 0.3% | 2025-Q2 stale |
| WHITEBOX ADVISORS LLC trimmed | 115,000 | $2M | 0.3% | 2025-Q3 stale |
| JANE STREET GROUP, LLC added | 301,213 | $2M | 0.3% | 2025-Q4 stale |
| BlueCrest Capital Management Ltd new | 110,644 | $2M | 0.3% | 2025-Q3 stale |
| WEXFORD CAPITAL LP added | 102,712 | $2M | 0.3% | 2025-Q3 stale |
| Mint Tower Capital Management B.V. | 144,903 | $2M | 0.2% | 2025-Q2 stale |
| TENOR CAPITAL MANAGEMENT Co., L.P. trimmed | 142,960 | $2M | 0.2% | 2025-Q2 stale |
| HIGHBRIDGE CAPITAL MANAGEMENT LLC trimmed | 244,000 | $1M | 0.2% | 2025-Q4 stale |
| DANSKE BANK A/S new | 213,401 | $1M | 0.2% | 2025-Q4 stale |
| Bulldog Investors, LLP trimmed | 113,348 | $1M | 0.2% | 2025-Q2 stale |
| DELTEC ASSET MANAGEMENT LLC trimmed | 75,000 | $1M | 0.2% | 2025-Q3 stale |
| Hidden Lake Asset Management LP new | 99,370 | $1M | 0.2% | 2025-Q2 stale |
| SIMPLEX TRADING, LLC new | 48,514 | $796K | 0.1% | 2025-Q3 stale |
| PICTON MAHONEY ASSET MANAGEMENT trimmed | 42,081 | $691K | 0.1% | 2025-Q3 stale |
| Context Capital Management, LLC trimmed | 54,800 | $608K | 0.1% | 2025-Q2 stale |
| XTX Topco Ltd new | 97,218 | $594K | 0.1% | 2025-Q4 stale |
| Decagon Asset Management LLP new | 56,178 | $591K | 0.1% | 2025-Q1 stale |
| Shaolin Capital Management LLC new | 50,000 | $555K | 0.1% | 2025-Q2 stale |
| SkyView Investment Advisors, LLC new | 83,844 | $512K | 0.1% | 2025-Q4 stale |
| FIFTH LANE CAPITAL, LP new | 45,000 | $500K | 0.1% | 2025-Q2 stale |
| Jump Financial, LLC new | 77,900 | $476K | 0.1% | 2025-Q4 stale |
| NATIONS FINANCIAL GROUP INC, /IA/ /ADV new | 27,047 | $444K | 0.1% | 2025-Q3 stale |
| Yaupon Capital Management LP new | 35,139 | $390K | 0.1% | 2025-Q2 stale |
| GLAZER CAPITAL, LLC new | 36,831 | $387K | 0.1% | 2025-Q1 stale |
| Private Advisor Group, LLC new | 22,841 | $375K | 0.1% | 2025-Q3 stale |
| TWO SIGMA INVESTMENTS, LP trimmed | 57,712 | $353K | 0.1% | 2025-Q4 stale |
| Engineers Gate Manager LP new | 51,654 | $316K | 0.0% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.