Who owns KOS (KOS)
Which tracked institutional funds hold KOS, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See KOS 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
The tracked-fund tape on KOS is one-sided between 2025-Q4 and 2026-Q1: 119 added or opened and 6 trimmed or exited — on balance accumulating.
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
KOS’s largest tracked holder by dollar value, BlackRock, Inc., 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 KOS more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in KOS 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 262 tracked filers holding KOS, 173 increased or opened the position and 96 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases.
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 KOS 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 42
- VANGUARD PORTFOLIO MANAGEMENT LLC$24M
- Davidson Kempner Capital Management LP$23M
- VANGUARD CAPITAL MANAGEMENT LLC$18M
- Boston Partners$13M
- Monaco Asset Management SAM$11M
- Ghisallo Capital Management LLC$10M
Full exits 3
- VANGUARD GROUP INC$13M
- TWO SIGMA ADVISERS, LP$2M
- GROUP ONE TRADING LLC$803K
Largest adds
- BlackRock, Inc.$89M
- STATE STREET CORP$60M
- TWO SIGMA INVESTMENTS, LP$48M
- Equinox Partners Investment Management LLC$40M
- D. E. Shaw & Co., Inc.$38M
- HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC$37M
Largest trims
- AMERICAN CENTURY COMPANIES INC$10M
- RAYMOND JAMES FINANCIAL INC$659K
- Graham Capital Management, L.P.$471K
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 |
|---|---|---|---|---|
| BlackRock, Inc. added | 47,463,094 | $132M | 10.5% | 2026-Q1 |
| STATE STREET CORP added | 28,247,797 | $79M | 6.2% | 2026-Q1 |
| Equinox Partners Investment Management LLC added | 20,678,033 | $57M | 4.6% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 20,247,384 | $56M | 4.5% | 2026-Q1 |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC trimmed | 20,051,601 | $56M | 4.4% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 18,680,328 | $52M | 4.1% | 2026-Q1 |
| Grantham, Mayo, Van Otterloo & Co. LLC trimmed | 18,307,718 | $51M | 4.0% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 14,135,448 | $39M | 3.1% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 12,714,055 | $35M | 2.8% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 12,632,904 | $35M | 2.8% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 11,743,115 | $33M | 2.6% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 9,261,696 | $26M | 2.0% | 2026-Q1 |
| Invesco Ltd. added | 8,853,928 | $25M | 2.0% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 8,619,103 | $24M | 1.9% | 2026-Q1 |
| Davidson Kempner Capital Management LP new | 8,419,986 | $23M | 1.9% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 7,694,248 | $21M | 1.7% | 2026-Q1 |
| M&G PLC trimmed | 7,031,872 | $21M | 1.7% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 7,083,075 | $20M | 1.6% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 6,422,390 | $18M | 1.4% | 2026-Q1 |
| Russell Investments Group, Ltd. trimmed | 5,857,655 | $16M | 1.3% | 2026-Q1 |
| MORGAN STANLEY added | 5,837,077 | $16M | 1.3% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 5,541,020 | $15M | 1.2% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 5,339,638 | $15M | 1.2% | 2026-Q1 |
| UBS Group AG trimmed | 4,812,090 | $13M | 1.1% | 2026-Q1 |
| Boston Partners added | 4,756,571 | $13M | 1.1% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 4,450,077 | $12M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 4,231,394 | $12M | 0.9% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 4,153,678 | $12M | 0.9% | 2026-Q1 |
| Monaco Asset Management SAM new | 4,045,884 | $11M | 0.9% | 2026-Q1 |
| VAUGHAN NELSON INVESTMENT MANAGEMENT, L.P. | 4,008,525 | $11M | 0.9% | 2026-Q1 |
| OSTRUM ASSET MANAGEMENT | 4,008,525 | $11M | 0.9% | 2026-Q1 |
| Ghisallo Capital Management LLC added | 3,675,000 | $10M | 0.8% | 2026-Q1 |
| Nuveen, LLC added | 3,314,644 | $9M | 0.7% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 3,232,465 | $9M | 0.7% | 2026-Q1 |
| Covalis Capital LLP added | 3,162,820 | $9M | 0.7% | 2026-Q1 |
| HRT FINANCIAL LP added | 2,719,928 | $8M | 0.6% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 2,551,897 | $8M | 0.6% | 2026-Q1 |
| NOMURA HOLDINGS INC added | 2,354,135 | $7M | 0.5% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 2,347,639 | $7M | 0.5% | 2026-Q1 |
| Walleye Capital LLC added | 2,314,477 | $6M | 0.5% | 2026-Q1 |
| GeoSphere Capital Management, LLC added | 2,038,788 | $6M | 0.5% | 2026-Q1 |
| Ballast Asset Management, LP added | 2,028,059 | $6M | 0.4% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 1,964,598 | $5M | 0.4% | 2026-Q1 |
| Nantahala Capital Management, LLC trimmed | 1,844,194 | $5M | 0.4% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 1,729,874 | $5M | 0.4% | 2026-Q1 |
| BARCLAYS PLC trimmed | 1,654,710 | $5M | 0.4% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 1,559,792 | $4M | 0.3% | 2026-Q1 |
| SEI INVESTMENTS CO added | 1,515,992 | $4M | 0.3% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 1,507,387 | $4M | 0.3% | 2026-Q1 |
| Quadrature Capital Ltd added | 1,474,133 | $4M | 0.3% | 2026-Q1 |
| J. Goldman & Co LP new | 1,443,749 | $4M | 0.3% | 2026-Q1 |
| LPL Financial LLC added | 1,404,359 | $4M | 0.3% | 2026-Q1 |
| Rafferty Asset Management, LLC added | 1,347,730 | $4M | 0.3% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 1,256,867 | $3M | 0.3% | 2026-Q1 |
| Quantbot Technologies LP added | 1,231,912 | $3M | 0.3% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 1,181,323 | $3M | 0.3% | 2026-Q1 |
| Swiss National Bank added | 1,106,800 | $3M | 0.2% | 2026-Q1 |
| ExodusPoint Capital Management, LP added | 1,096,323 | $3M | 0.2% | 2026-Q1 |
| LMR Partners LLP new | 1,036,943 | $3M | 0.2% | 2026-Q1 |
| Purpose Unlimited Inc. new | 1,000,000 | $3M | 0.2% | 2026-Q1 |
| FIRST SABREPOINT CAPITAL MANAGEMENT LP added | 1,000,000 | $3M | 0.2% | 2026-Q1 |
| Susquehanna Portfolio Strategies, LLC new | 990,888 | $3M | 0.2% | 2026-Q1 |
| Thomist Capital Management, LP added | 927,209 | $3M | 0.2% | 2026-Q1 |
| Aquatic Capital Management LLC added | 923,417 | $3M | 0.2% | 2026-Q1 |
| CenterBook Partners LP new | 891,474 | $2M | 0.2% | 2026-Q1 |
| CAXTON ASSOCIATES LLP added | 828,839 | $2M | 0.2% | 2026-Q1 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 759,700 | $2M | 0.2% | 2026-Q1 |
| Raiffeisen Bank International AG trimmed | 700,000 | $2M | 0.2% | 2026-Q1 |
| XTX Topco Ltd trimmed | 727,213 | $2M | 0.2% | 2026-Q1 |
| SG Americas Securities, LLC added | 722,891 | $2M | 0.2% | 2026-Q1 |
| GRATIA CAPITAL, LLC new | 719,800 | $2M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 700,026 | $2M | 0.2% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 663,917 | $2M | 0.1% | 2026-Q1 |
| HARBOR CAPITAL ADVISORS, INC. added | 653,420 | $2M | 0.1% | 2026-Q1 |
| CITIGROUP INC trimmed | 623,677 | $2M | 0.1% | 2026-Q1 |
| Portolan Capital Management, LLC trimmed | 602,542 | $2M | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 590,100 | $2M | 0.1% | 2026-Q1 |
| Creative Planning added | 514,155 | $1M | 0.1% | 2026-Q1 |
| IMC-Chicago, LLC added | 508,873 | $1M | 0.1% | 2026-Q1 |
| Aventail Capital Group, LP | 500,000 | $1M | 0.1% | 2026-Q1 |
| Centiva Capital, LP added | 495,305 | $1M | 0.1% | 2026-Q1 |
| WINTON GROUP Ltd added | 487,200 | $1M | 0.1% | 2026-Q1 |
| Moors & Cabot, Inc. added | 438,950 | $1M | 0.1% | 2026-Q1 |
| DEUTSCHE BANK AG\ added | 432,137 | $1M | 0.1% | 2026-Q1 |
| Man Group plc added | 430,613 | $1M | 0.1% | 2026-Q1 |
| VANGUARD ASSET MANAGEMENT, Ltd new | 392,801 | $1M | 0.1% | 2026-Q1 |
| WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC trimmed | 17,169,011 | $39M | 3.1% | 2025-Q1 stale |
| VANGUARD GROUP INC added | 14,836,244 | $13M | 1.1% | 2025-Q4 stale |
| Corigliano Investment Advisers, LLC new | 3,090,869 | $7M | 0.6% | 2025-Q1 stale |
| Hartree Partners, LP trimmed | 8,000,000 | $6M | 0.5% | 2025-Q2 stale |
| Patient Capital Management, LLC trimmed | 3,314,653 | $6M | 0.4% | 2025-Q3 stale |
| First Eagle Investment Management, LLC added | 2,747,831 | $5M | 0.4% | 2025-Q3 stale |
| RWC ASSET ADVISORS (US) LLC trimmed | 2,255,539 | $4M | 0.3% | 2025-Q2 stale |
| ROYCE & ASSOCIATES LP added | 1,980,830 | $3M | 0.3% | 2025-Q2 stale |
| ABN AMRO INVESTMENT SOLUTIONS added | 1,172,798 | $3M | 0.2% | 2025-Q1 stale |
| Black Maple Capital Management LP added | 1,135,552 | $3M | 0.2% | 2025-Q1 stale |
| TWO SIGMA ADVISERS, LP added | 1,834,222 | $2M | 0.1% | 2025-Q4 stale |
| VAN ECK ASSOCIATES CORP added | 964,671 | $2M | 0.1% | 2025-Q3 stale |
| FORT WASHINGTON INVESTMENT ADVISORS INC /OH/ | 675,217 | $1M | 0.1% | 2025-Q3 stale |
| Caption Management, LLC added | 661,628 | $1M | 0.1% | 2025-Q3 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.