Who owns OS (OS)
Which tracked institutional funds hold OS, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See OS 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
97 tracked funds added or opened OS while 68 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
OS’s largest tracked holder by dollar value, GLAZER CAPITAL, LLC, sizes it at 4.0% of its own reported 13F book, while the median holder sizes it at 0.1% of theirs — a 3.9pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in OS 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 180 tracked filers holding OS, 132 increased or opened the position and 123 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
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 OS 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 59
- GLAZER CAPITAL, LLC$181M
- VANGUARD PORTFOLIO MANAGEMENT LLC$118M
- FIL Ltd$96M
- VANGUARD CAPITAL MANAGEMENT LLC$93M
- AQR Arbitrage LLC$81M
- NEXPOINT ASSET MANAGEMENT, L.P.$81M
Full exits 51
- VANGUARD GROUP INC$147M
- DARLINGTON PARTNERS CAPITAL MANAGEMENT, LP$71M
- T. Rowe Price Investment Management, Inc.$71M
- BROWN ADVISORY INC$62M
- TimesSquare Capital Management, LLC$49M
- FULLER & THALER ASSET MANAGEMENT, INC.$48M
Largest adds
- MILLENNIUM MANAGEMENT LLC$53M
- UBS Group AG$45M
- SOROS FUND MANAGEMENT LLC$38M
- HSBC HOLDINGS PLC$38M
- GOLDMAN SACHS GROUP INC$35M
- JPMORGAN CHASE & CO$30M
Largest trims
- KAYNE ANDERSON RUDNICK INVESTMENT MANAGEMENT LLC$89M
- NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO$41M
- MARSHALL WACE, LLP$27M
- ExodusPoint Capital Management, LP$8M
- Point72 Asset Management, L.P.$8M
- WELLS FARGO & COMPANY/MN$8M
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 |
|---|---|---|---|---|
| GLAZER CAPITAL, LLC new | 7,537,536 | $181M | 5.9% | 2026-Q1 |
| NORGES BANK added | 6,239,761 | $133M | 4.3% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 4,900,450 | $118M | 3.8% | 2026-Q1 |
| Temasek Holdings (Private) Ltd | 4,266,714 | $102M | 3.3% | 2026-Q1 |
| FIL Ltd new | 3,992,145 | $96M | 3.1% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 3,882,231 | $93M | 3.0% | 2026-Q1 |
| AQR Arbitrage LLC new | 3,393,367 | $81M | 2.7% | 2026-Q1 |
| NEXPOINT ASSET MANAGEMENT, L.P. new | 3,358,217 | $81M | 2.6% | 2026-Q1 |
| O'Connor Alternative Investments LLC new | 3,186,804 | $76M | 2.5% | 2026-Q1 |
| Polar Asset Management Partners Inc. new | 2,944,378 | $71M | 2.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 2,471,107 | $59M | 1.9% | 2026-Q1 |
| BlackRock, Inc. added | 2,339,550 | $56M | 1.8% | 2026-Q1 |
| UBS Group AG added | 2,257,069 | $54M | 1.8% | 2026-Q1 |
| Man Group plc added | 2,204,520 | $53M | 1.7% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 1,985,820 | $48M | 1.6% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 1,890,118 | $45M | 1.5% | 2026-Q1 |
| Pentwater Capital Management LP new | 1,890,000 | $45M | 1.5% | 2026-Q1 |
| First Trust Capital Management L.P. new | 1,842,189 | $44M | 1.4% | 2026-Q1 |
| SOROS FUND MANAGEMENT LLC added | 1,830,222 | $44M | 1.4% | 2026-Q1 |
| TIG Advisors, LLC new | 1,738,231 | $42M | 1.4% | 2026-Q1 |
| MORGAN STANLEY added | 1,651,031 | $40M | 1.3% | 2026-Q1 |
| HSBC HOLDINGS PLC added | 1,595,839 | $38M | 1.2% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 1,467,884 | $35M | 1.1% | 2026-Q1 |
| ODDO BHF ASSET MANAGEMENT SAS new | 1,450,000 | $35M | 1.1% | 2026-Q1 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND added | 1,234,961 | $30M | 1.0% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. trimmed | 1,535,061 | $28M | 0.9% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 1,133,221 | $27M | 0.9% | 2026-Q1 |
| CITIGROUP INC added | 1,103,394 | $26M | 0.9% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,099,122 | $26M | 0.9% | 2026-Q1 |
| Capula Management Ltd new | 1,074,711 | $26M | 0.8% | 2026-Q1 |
| MARSHALL WACE, LLP trimmed | 988,636 | $24M | 0.8% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 984,652 | $24M | 0.8% | 2026-Q1 |
| ALPINE ASSOCIATES MANAGEMENT INC. new | 920,692 | $22M | 0.7% | 2026-Q1 |
| Verition Fund Management LLC added | 862,413 | $21M | 0.7% | 2026-Q1 |
| METEORA CAPITAL, LLC new | 861,800 | $21M | 0.7% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 817,569 | $20M | 0.6% | 2026-Q1 |
| SYQUANT CAPITAL SAS new | 789,449 | $19M | 0.6% | 2026-Q1 |
| Nearwater Capital Markets, Ltd new | 707,800 | $17M | 0.6% | 2026-Q1 |
| Fort Baker Capital Management LP new | 689,587 | $17M | 0.5% | 2026-Q1 |
| Westchester Capital Management, LLC new | 677,498 | $16M | 0.5% | 2026-Q1 |
| Grantham, Mayo, Van Otterloo & Co. LLC new | 676,553 | $16M | 0.5% | 2026-Q1 |
| Alberta Investment Management Corp added | 674,500 | $16M | 0.5% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 623,975 | $15M | 0.5% | 2026-Q1 |
| STATE STREET CORP trimmed | 600,024 | $14M | 0.5% | 2026-Q1 |
| GABELLI FUNDS LLC new | 523,583 | $13M | 0.4% | 2026-Q1 |
| CIBRA Capital Ltd new | 519,691 | $12M | 0.4% | 2026-Q1 |
| Squarepoint Ops LLC added | 518,231 | $12M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 511,124 | $12M | 0.4% | 2026-Q1 |
| Groupe la Francaise new | 509,500 | $12M | 0.4% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 499,512 | $12M | 0.4% | 2026-Q1 |
| GABELLI & Co INVESTMENT ADVISERS, INC. new | 408,372 | $10M | 0.3% | 2026-Q1 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 396,426 | $10M | 0.3% | 2026-Q1 |
| CREDIT INDUSTRIEL ET COMMERCIAL new | 365,500 | $9M | 0.3% | 2026-Q1 |
| Taconic Capital Advisors LP new | 341,528 | $8M | 0.3% | 2026-Q1 |
| TPG GP A, LLC new | 325,000 | $8M | 0.3% | 2026-Q1 |
| FIFTH LANE CAPITAL, LP new | 322,630 | $8M | 0.3% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 313,565 | $8M | 0.2% | 2026-Q1 |
| TOKIO MARINE ASSET MANAGEMENT CO LTD new | 284,300 | $7M | 0.2% | 2026-Q1 |
| PICTON MAHONEY ASSET MANAGEMENT added | 274,000 | $7M | 0.2% | 2026-Q1 |
| Trium Capital LLP new | 272,803 | $7M | 0.2% | 2026-Q1 |
| Absolute Gestao de Investimentos Ltda. new | 245,160 | $6M | 0.2% | 2026-Q1 |
| NORTHERN TRUST CORP added | 240,517 | $6M | 0.2% | 2026-Q1 |
| Annis Gardner Whiting Capital Advisors, LLC added | 227,217 | $5M | 0.2% | 2026-Q1 |
| SG Americas Securities, LLC trimmed | 218,311 | $5M | 0.2% | 2026-Q1 |
| New York Life Investment Management LLC new | 215,678 | $5M | 0.2% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 7,997,849 | $147M | 4.8% | 2025-Q4 stale |
| DARLINGTON PARTNERS CAPITAL MANAGEMENT, LP | 3,839,405 | $71M | 2.3% | 2025-Q4 stale |
| T. Rowe Price Investment Management, Inc. trimmed | 3,839,359 | $71M | 2.3% | 2025-Q4 stale |
| BROWN ADVISORY INC trimmed | 3,376,401 | $62M | 2.0% | 2025-Q4 stale |
| TimesSquare Capital Management, LLC added | 2,668,307 | $49M | 1.6% | 2025-Q4 stale |
| FULLER & THALER ASSET MANAGEMENT, INC. new | 2,592,382 | $48M | 1.6% | 2025-Q4 stale |
| Champlain Investment Partners, LLC trimmed | 2,116,556 | $39M | 1.3% | 2025-Q4 stale |
| WELLINGTON MANAGEMENT GROUP LLP added | 1,342,754 | $25M | 0.8% | 2025-Q4 stale |
| WASATCH ADVISORS LP added | 1,334,873 | $25M | 0.8% | 2025-Q4 stale |
| NEUBERGER BERMAN GROUP LLC trimmed | 1,281,694 | $24M | 0.8% | 2025-Q4 stale |
| AMERICAN CENTURY COMPANIES INC added | 1,271,265 | $23M | 0.8% | 2025-Q4 stale |
| MOORE CAPITAL MANAGEMENT, LP added | 1,204,698 | $22M | 0.7% | 2025-Q4 stale |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ trimmed | 1,050,802 | $19M | 0.6% | 2025-Q4 stale |
| FEDERATED HERMES, INC. | 850,000 | $16M | 0.5% | 2025-Q4 stale |
| Clearbridge Investments, LLC added | 613,505 | $11M | 0.4% | 2025-Q4 stale |
| D. E. Shaw & Co., Inc. added | 371,251 | $11M | 0.3% | 2025-Q2 stale |
| JACOBS LEVY EQUITY MANAGEMENT, INC trimmed | 366,734 | $10M | 0.3% | 2025-Q2 stale |
| Tensile Capital Management LP new | 541,070 | $10M | 0.3% | 2025-Q4 stale |
| Alyeska Investment Group, L.P. added | 530,341 | $10M | 0.3% | 2025-Q4 stale |
| ALKEON CAPITAL MANAGEMENT LLC trimmed | 475,000 | $9M | 0.3% | 2025-Q4 stale |
| Ghisallo Capital Management LLC new | 300,000 | $8M | 0.3% | 2025-Q2 stale |
| TD Asset Management Inc trimmed | 438,496 | $8M | 0.3% | 2025-Q4 stale |
| Burkehill Global Management, LP trimmed | 400,000 | $7M | 0.2% | 2025-Q3 stale |
| Voya Investment Management LLC new | 258,834 | $7M | 0.2% | 2025-Q2 stale |
| Capricorn Fund Managers Ltd new | 380,000 | $7M | 0.2% | 2025-Q4 stale |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC trimmed | 353,662 | $7M | 0.2% | 2025-Q4 stale |
| ARMISTICE CAPITAL, LLC added | 336,000 | $6M | 0.2% | 2025-Q4 stale |
| M&T Bank Corp trimmed | 34,160 | $6M | 0.2% | 2025-Q4 stale |
| EVERGREEN CAPITAL MANAGEMENT LLC trimmed | 325,113 | $6M | 0.2% | 2025-Q4 stale |
| Centiva Capital, LP new | 204,950 | $6M | 0.2% | 2025-Q2 stale |
| Fortress Investment Group LLC added | 198,846 | $6M | 0.2% | 2025-Q2 stale |
| SEI INVESTMENTS CO trimmed | 301,913 | $6M | 0.2% | 2025-Q4 stale |
| Aperture Investors, LLC trimmed | 236,118 | $5M | 0.2% | 2025-Q1 stale |
| CAPSTONE INVESTMENT ADVISORS, LLC new | 175,000 | $5M | 0.2% | 2025-Q2 stale |
| KING LUTHER CAPITAL MANAGEMENT CORP added | 268,054 | $5M | 0.2% | 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.