Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
325 institutional managers reported holding GKOS for the quarter ended Mar 31, 2026. Reported positions total over 95% of shares outstanding; the top 10 hold 58%. 43 opened new positions; 45 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 9.09M | 15.67% | $979.6M | trimmed -0.8% | 2015 Q3 |
| Vanguard Group | 6.21M | 10.70% | $669.1M | added +3.1% | 2015 Q2 |
| Janus Henderson | 5.35M | 9.22% | $576.4M | added +77.2% | 2016 Q3 |
| PRIMECAP Management | 3.37M | 5.81% | $363.2M | unchanged | 2017 Q4 |
| State Street | 2.18M | 3.76% | $235.2M | added +2.8% | 2015 Q3 |
| Ameriprise Financial INC | 1.61M | 2.78% | $173.6M | trimmed -23.5% | 2015 Q2 |
| Citadel Advisors | 1.45M | 2.49% | $155.9M | added +5267.7% | 2018 Q2 |
| AllianceBernstein | 1.40M | 2.41% | $150.6M | trimmed -15% | 2015 Q2 |
| Holocene Advisors | 1.38M | 2.38% | $149.1M | added +6.5% | 2024 Q4 |
| Goldman Sachs | 1.37M | 2.37% | $148.2M | added +1.8% | 2016 Q2 |
| Geode Capital | 1.36M | 2.34% | $146.2M | added +2.9% | 2015 Q3 |
| Millennium Management | 1.17M | 2.02% | $126.5M | trimmed -27.1% | 2015 Q2 |
| William Blair Investment Management, LLC | 1.07M | 1.85% | $115.7M | trimmed -3% | 2024 Q4 |
| Capital Group (American Funds) | 989.1k | 1.71% | $106.6M | added +16.2% | 2015 Q2 |
| Invesco | 914.2k | 1.58% | $98.5M | added +17.2% | 2018 Q3 |
| Braidwell LP | 763.5k | 1.32% | $82.3M | trimmed -17.2% | 2022 Q4 |
| Charles Schwab Investment Management | 714.4k | 1.23% | $77.0M | unchanged | 2015 Q4 |
| Morgan Stanley | 678.8k | 1.17% | $73.2M | added +1.2% | 2015 Q2 |
| Bank OF America CORP /DE/ | 657.4k | 1.13% | $70.8M | added +22% | 2015 Q2 |
| Nomura Asset Management International INC. | 612.1k | 1.05% | $66.0M | trimmed -9% | 2025 Q4 |
| Artisan Partners | 607.5k | 1.05% | $65.5M | trimmed -13.6% | 2016 Q3 |
| Northern Trust | 576.2k | 0.99% | $62.1M | trimmed -1.9% | 2015 Q3 |
| UBS | 530.2k | 0.91% | $57.1M | trimmed -47.9% | 2015 Q2 |
| Driehaus Capital Management LLC | 487.9k | 0.84% | $52.6M | opened | 2026 Q1 |
| Jennison Associates LLC | 487.0k | 0.84% | $52.5M | opened | 2026 Q1 |
| Westfield Capital Management CO LP | 482.2k | 0.83% | $52.0M | opened | 2024 Q3 |
| Riverbridge Partners LLC | 433.2k | 0.75% | $46.7M | trimmed -19% | 2021 Q2 |
| Loomis Sayles & CO L P | 421.2k | 0.73% | $45.4M | trimmed -5.9% | 2023 Q4 |
| Nuveen | 398.3k | 0.69% | $42.9M | trimmed -1.9% | 2019 Q2 |
| Allspring Global Investments Holdings, LLC | 393.8k | 0.68% | $42.4M | added +10.9% | 2021 Q4 |
| Capital International Investors | 373.3k | 0.64% | $40.2M | trimmed -27% | 2025 Q2 |
| BNY Mellon | 343.2k | 0.59% | $37.0M | trimmed -3.6% | 2015 Q3 |
| T. Rowe Price | 336.4k | 0.58% | $36.3M | added +175.4% | 2017 Q1 |
| Champlain Investment Partners, LLC | 319.0k | 0.55% | $34.4M | trimmed -4.3% | 2025 Q2 |
| FMR (Fidelity) | 303.3k | 0.52% | $32.7M | added +2907.7% | 2018 Q1 |
| Clearbridge Investments, LLC | 286.1k | 0.49% | $30.8M | added +155.4% | 2025 Q1 |
| Principal Financial Group INC | 280.7k | 0.48% | $30.3M | added +2.2% | 2021 Q4 |
| D. E. Shaw | 251.2k | 0.43% | $27.1M | trimmed -55% | 2022 Q3 |
| Brown Capital Management LLC | 230.0k | 0.40% | $24.8M | trimmed -29.6% | 2018 Q4 |
| PFM Health Sciences, LP | 215.7k | 0.37% | $23.2M | added +6.9% | 2025 Q4 |
| C WorldWide Group Holding A/S | 207.2k | 0.36% | $22.3M | unchanged | 2016 Q2 |
| Public Sector Pension Investment Board | 205.5k | 0.35% | $22.1M | added +3.4% | 2020 Q1 |
| Royal Bank OF Canada | 204.2k | 0.35% | $22.0M | added +6.4% | 2015 Q2 |
| Dimensional Fund Advisors | 199.1k | 0.34% | $21.5M | trimmed -3.1% | 2021 Q2 |
| ExodusPoint | 179.7k | 0.31% | $19.4M | opened | 2026 Q1 |
| Integral Health Asset Management, LLC | 175.0k | 0.30% | $18.9M | trimmed -46.2% | 2025 Q2 |
| SEI Investments CO | 161.7k | 0.28% | $17.4M | trimmed -11.1% | 2018 Q1 |
| Legal & General Group PLC | 160.5k | 0.28% | $17.3M | trimmed -10.7% | 2016 Q2 |
| Rhumbline Advisers | 154.2k | 0.27% | $16.6M | added +1.8% | 2016 Q2 |
| Gilder Gagnon Howe & CO LLC | 152.9k | 0.26% | $16.5M | trimmed -1% | 2022 Q4 |
Largest 50 of 325 shown; the full ranked, searchable register is at boothcheck.com/holders/GKOS. 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.