Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
250 institutional managers reported holding KOS for the quarter ended Mar 31, 2026. Together they hold about 85% of shares outstanding; the top 10 hold 43%. 79 opened new positions; 35 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 47.46M | 9.38% | $131.9M | added +1.3% | ≤2013 |
| State Street | 28.25M | 5.58% | $78.5M | added +38.3% | ≤2013 |
| Equinox Partners Investment Management LLC (focused) | 20.68M | 4.08% | $57.5M | added +6.2% | 2022 Q1 |
| D. E. Shaw | 20.39M | 4.03% | $56.7M | added +241.7% | 2024 Q3 |
| Hotchkis & Wiley Capital Management LLC | 20.05M | 3.96% | $55.7M | unchanged | ≤2013 |
| Vanguard Group | 19.09M | 3.77% | $53.1M | added +28.5% | ≤2013 |
| Two Sigma | 18.68M | 3.69% | $51.9M | added +384.5% | 2025 Q1 |
| Grantham, Mayo, Van Otterloo & CO. LLC | 18.31M | 3.62% | $50.9M | trimmed -47.4% | 2020 Q2 |
| Charles Schwab Investment Management | 14.14M | 2.79% | $39.3M | added +17.3% | ≤2013 |
| Geode Capital | 12.71M | 2.51% | $35.3M | added +12.8% | ≤2013 |
| Millennium Management | 12.63M | 2.50% | $35.1M | trimmed -14.8% | ≤2013 |
| Jane Street | 11.74M | 2.32% | $32.6M | added +26.7% | 2017 Q3 |
| Invesco | 11.15M | 2.20% | $31.0M | added +496% | ≤2013 |
| Goldman Sachs | 9.26M | 1.83% | $25.7M | added +36.9% | ≤2013 |
| UBS | 8.97M | 1.77% | $24.9M | trimmed -10.6% | ≤2013 |
| Davidson Kempner | 8.42M | 1.66% | $23.4M | opened | 2026 Q1 |
| First Trust Advisors LP | 7.69M | 1.52% | $21.4M | added +9.2% | 2018 Q2 |
| Dimensional Fund Advisors | 7.08M | 1.40% | $19.7M | added +20.5% | ≤2013 |
| M&G PLC | 7.03M | 1.39% | $19.5M | trimmed -19.5% | 2019 Q4 |
| Russell Investments Group, LTD. | 5.86M | 1.16% | $16.3M | unchanged | 2020 Q1 |
| Morgan Stanley | 5.84M | 1.15% | $16.2M | added +24% | ≤2013 |
| Bank OF America CORP /DE/ | 5.54M | 1.09% | $15.4M | added +43.9% | ≤2013 |
| Renaissance Technologies | 5.34M | 1.05% | $14.8M | added +224% | 2025 Q3 |
| Boston Partners | 4.76M | 0.94% | $13.2M | opened | 2026 Q1 |
| Citadel Advisors | 4.45M | 0.88% | $12.4M | trimmed -19.9% | ≤2013 |
| Northern Trust | 4.23M | 0.84% | $11.8M | added +15.3% | ≤2013 |
| Monaco Asset Management SAM | 4.05M | 0.80% | $11.2M | opened | 2026 Q1 |
| Vaughan Nelson Investment Management, L.p. | 4.01M | 0.79% | $11.1M | unchanged | 2016 Q4 |
| Ostrum Asset Management | 4.01M | 0.79% | $11.1M | unchanged | 2025 Q1 |
| Ghisallo Capital Management LLC | 3.67M | 0.73% | $10.2M | opened | 2026 Q1 |
| Nuveen | 3.31M | 0.66% | $9.2M | added +144.1% | 2019 Q2 |
| Covalis Capital LLP | 3.16M | 0.63% | $8.8M | opened | 2026 Q1 |
| HRT Financial LP | 2.72M | 0.54% | $7.6M | opened | 2026 Q1 |
| Nomura Asset Management International INC. | 2.35M | 0.47% | $6.5M | added +129.4% | 2023 Q2 |
| Susquehanna International Group | 2.35M | 0.46% | $6.5M | trimmed -4.4% | 2017 Q2 |
| Walleye Capital LLC | 2.33M | 0.46% | $6.5M | added +15834.2% | 2024 Q1 |
| GeoSphere Capital Management, LLC (focused) | 2.04M | 0.40% | $5.7M | opened | 2026 Q1 |
| Ballast Asset Management, LP | 2.03M | 0.40% | $5.6M | added +11.4% | 2023 Q3 |
| Point72 | 1.96M | 0.39% | $5.5M | added +216.3% | 2025 Q2 |
| Nantahala Capital Management, LLC | 1.84M | 0.36% | $5.1M | trimmed -21.3% | 2025 Q1 |
| Arrowstreet Capital | 1.73M | 0.34% | $4.8M | opened | 2026 Q1 |
| Barclays PLC | 1.65M | 0.33% | $4.6M | trimmed -19.2% | ≤2013 |
| Wells Fargo & COMPANY/MN | 1.56M | 0.31% | $4.3M | trimmed -9.7% | ≤2013 |
| SEI Investments CO | 1.52M | 0.30% | $4.2M | added +76.8% | 2014 Q2 |
| BNY Mellon | 1.51M | 0.30% | $4.2M | trimmed -1.2% | ≤2013 |
| Quadrature Capital LTD | 1.47M | 0.29% | $4.1M | opened | 2024 Q3 |
| J. Goldman & CO LP | 1.44M | 0.28% | $4.0M | opened | 2026 Q1 |
| LPL Financial LLC | 1.40M | 0.28% | $3.9M | opened | 2022 Q2 |
| Rafferty Asset Management, LLC | 1.35M | 0.27% | $3.7M | added +66.2% | 2021 Q2 |
| AQR Capital | 1.29M | 0.26% | $3.6M | added +140.9% | 2018 Q2 |
Largest 50 of 250 shown; the full ranked, searchable register is at boothcheck.com/holders/KOS. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.