Who owns GKOS (GKOS)
Which tracked institutional funds hold GKOS, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See GKOS 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
61 tracked funds added or opened GKOS while 113 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
GKOS’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 GKOS more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in GKOS 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 336 tracked filers holding GKOS, 161 increased or opened the position and 173 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 GKOS 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 24
- VANGUARD PORTFOLIO MANAGEMENT LLC$345M
- VANGUARD CAPITAL MANAGEMENT LLC$270M
- Driehaus Capital Management LLC$53M
- JENNISON ASSOCIATES LLC$52M
- WESTFIELD CAPITAL MANAGEMENT CO LP$52M
- VANGUARD FIDUCIARY TRUST CO$43M
Full exits 20
- VANGUARD GROUP INC$670M
- Sofinnova Investments, Inc.$33M
- PERCEPTIVE ADVISORS LLC$16M
- Defilade Capital Management, L.P.$10M
- Balyasny Asset Management L.P.$10M
- TWO SIGMA ADVISERS, LP$8M
Largest adds
- JANUS HENDERSON GROUP PLC$235M
- CITADEL ADVISORS LLC$153M
- FMR LLC$27M
- PRICE T ROWE ASSOCIATES INC /MD/$22M
- Clearbridge Investments, LLC$18M
- Capital World Investors$10M
Largest trims
- BlackRock, Inc.$173M
- AMERIPRISE FINANCIAL INC$64M
- UBS Group AG$57M
- MILLENNIUM MANAGEMENT LLC$55M
- WELLINGTON MANAGEMENT GROUP LLP$39M
- AustralianSuper Pty Ltd$37M
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. trimmed | 8,007,326 | $862M | 12.6% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 5,348,395 | $576M | 8.4% | 2026-Q1 |
| PRIMECAP MANAGEMENT CO/CA/ trimmed | 3,370,628 | $363M | 5.3% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 3,208,363 | $345M | 5.0% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 2,508,771 | $270M | 3.9% | 2026-Q1 |
| STATE STREET CORP added | 2,182,617 | $235M | 3.4% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 1,610,774 | $173M | 2.5% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. trimmed | 1,397,556 | $158M | 2.3% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 1,446,926 | $156M | 2.3% | 2026-Q1 |
| Holocene Advisors, LP added | 1,383,715 | $149M | 2.2% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 1,374,958 | $148M | 2.2% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,356,453 | $146M | 2.1% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 1,173,696 | $126M | 1.8% | 2026-Q1 |
| WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC trimmed | 1,073,819 | $116M | 1.7% | 2026-Q1 |
| Capital World Investors added | 989,060 | $106M | 1.6% | 2026-Q1 |
| Invesco Ltd. added | 867,363 | $93M | 1.4% | 2026-Q1 |
| BRAIDWELL LP trimmed | 763,505 | $82M | 1.2% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 714,389 | $77M | 1.1% | 2026-Q1 |
| MORGAN STANLEY added | 678,825 | $73M | 1.1% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 657,432 | $71M | 1.0% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed | 612,063 | $66M | 1.0% | 2026-Q1 |
| Artisan Partners Limited Partnership trimmed | 607,462 | $65M | 1.0% | 2026-Q1 |
| NORGES BANK added | 654,931 | $64M | 0.9% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 576,209 | $62M | 0.9% | 2026-Q1 |
| Driehaus Capital Management LLC trimmed | 487,912 | $53M | 0.8% | 2026-Q1 |
| JENNISON ASSOCIATES LLC added | 487,020 | $52M | 0.8% | 2026-Q1 |
| WESTFIELD CAPITAL MANAGEMENT CO LP trimmed | 482,219 | $52M | 0.8% | 2026-Q1 |
| RIVERBRIDGE PARTNERS LLC trimmed | 433,228 | $47M | 0.7% | 2026-Q1 |
| LOOMIS SAYLES & CO L P trimmed | 421,240 | $45M | 0.7% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC added | 393,831 | $44M | 0.6% | 2026-Q1 |
| Nuveen, LLC trimmed | 398,329 | $43M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 396,719 | $43M | 0.6% | 2026-Q1 |
| UBS Group AG trimmed | 386,400 | $42M | 0.6% | 2026-Q1 |
| Capital International Investors trimmed | 373,343 | $40M | 0.6% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 343,173 | $37M | 0.5% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 336,425 | $36M | 0.5% | 2026-Q1 |
| Champlain Investment Partners, LLC trimmed | 319,027 | $34M | 0.5% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 323,819 | $34M | 0.5% | 2026-Q1 |
| Clearbridge Investments, LLC added | 286,051 | $31M | 0.4% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 280,737 | $30M | 0.4% | 2026-Q1 |
| FMR LLC added | 264,906 | $29M | 0.4% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 251,176 | $27M | 0.4% | 2026-Q1 |
| BROWN CAPITAL MANAGEMENT LLC trimmed | 230,028 | $25M | 0.4% | 2026-Q1 |
| PFM Health Sciences, LP added | 215,685 | $23M | 0.3% | 2026-Q1 |
| C WorldWide Group Holding A/S | 207,212 | $22M | 0.3% | 2026-Q1 |
| Public Sector Pension Investment Board added | 205,484 | $22M | 0.3% | 2026-Q1 |
| ROYAL BANK OF CANADA added | 204,153 | $22M | 0.3% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 199,084 | $21M | 0.3% | 2026-Q1 |
| ExodusPoint Capital Management, LP added | 179,728 | $19M | 0.3% | 2026-Q1 |
| Integral Health Asset Management, LLC trimmed | 175,000 | $19M | 0.3% | 2026-Q1 |
| SEI INVESTMENTS CO trimmed | 161,680 | $17M | 0.3% | 2026-Q1 |
| Legal & General Group Plc trimmed | 160,542 | $17M | 0.3% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 154,176 | $17M | 0.2% | 2026-Q1 |
| GILDER GAGNON HOWE & CO LLC trimmed | 152,897 | $16M | 0.2% | 2026-Q1 |
| EVENTIDE ASSET MANAGEMENT, LLC trimmed | 150,036 | $16M | 0.2% | 2026-Q1 |
| NEUBERGER BERMAN GROUP LLC added | 147,894 | $16M | 0.2% | 2026-Q1 |
| Bellevue Group AG trimmed | 145,703 | $16M | 0.2% | 2026-Q1 |
| KEYBANK NATIONAL ASSOCIATION/OH added | 145,270 | $16M | 0.2% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 144,372 | $16M | 0.2% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 143,774 | $15M | 0.2% | 2026-Q1 |
| AustralianSuper Pty Ltd trimmed | 131,535 | $14M | 0.2% | 2026-Q1 |
| SILVERCREST ASSET MANAGEMENT GROUP LLC added | 128,294 | $14M | 0.2% | 2026-Q1 |
| SEGALL BRYANT & HAMILL, LLC trimmed | 124,951 | $13M | 0.2% | 2026-Q1 |
| LORD, ABBETT & CO. LLC trimmed | 120,214 | $13M | 0.2% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 118,892 | $13M | 0.2% | 2026-Q1 |
| FRED ALGER MANAGEMENT, LLC trimmed | 113,943 | $12M | 0.2% | 2026-Q1 |
| Swiss National Bank added | 113,600 | $12M | 0.2% | 2026-Q1 |
| Granite Investment Partners, LLC trimmed | 111,872 | $12M | 0.2% | 2026-Q1 |
| Qube Research & Technologies Ltd trimmed | 108,863 | $12M | 0.2% | 2026-Q1 |
| Squarepoint Ops LLC trimmed | 108,049 | $12M | 0.2% | 2026-Q1 |
| Point72 Asset Management, L.P. trimmed | 101,340 | $11M | 0.2% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 98,226 | $10M | 0.2% | 2026-Q1 |
| OSTERWEIS CAPITAL MANAGEMENT INC trimmed | 94,863 | $10M | 0.1% | 2026-Q1 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. added | 94,538 | $10M | 0.1% | 2026-Q1 |
| WCM INVESTMENT MANAGEMENT, LLC trimmed | 93,427 | $10M | 0.1% | 2026-Q1 |
| Universal- Beteiligungs- und Servicegesellschaft mbH added | 87,752 | $9M | 0.1% | 2026-Q1 |
| Rhenman & Partners Asset Management AB trimmed | 84,000 | $9M | 0.1% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 81,878 | $9M | 0.1% | 2026-Q1 |
| ASSETMARK, INC added | 76,306 | $8M | 0.1% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 76,257 | $8M | 0.1% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 75,985 | $8M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 5,933,917 | $670M | 9.8% | 2025-Q4 stale |
| MACQUARIE GROUP LTD added | 600,228 | $49M | 0.7% | 2025-Q3 stale |
| Sofinnova Investments, Inc. trimmed | 288,128 | $33M | 0.5% | 2025-Q4 stale |
| Iron Triangle Partners LP added | 342,804 | $28M | 0.4% | 2025-Q3 stale |
| JANE STREET GROUP, LLC added | 307,183 | $25M | 0.4% | 2025-Q3 stale |
| Freestone Grove Partners LP added | 263,889 | $22M | 0.3% | 2025-Q3 stale |
| RTW INVESTMENTS, LP trimmed | 190,000 | $19M | 0.3% | 2025-Q1 stale |
| Polar Asset Management Partners Inc. added | 177,123 | $18M | 0.3% | 2025-Q2 stale |
| Atika Capital Management LLC trimmed | 212,400 | $17M | 0.3% | 2025-Q3 stale |
| PERCEPTIVE ADVISORS LLC added | 140,000 | $16M | 0.2% | 2025-Q4 stale |
| First Turn Management, LLC added | 136,241 | $13M | 0.2% | 2025-Q1 stale |
| Avidity Partners Management LP trimmed | 134,000 | $13M | 0.2% | 2025-Q1 stale |
| Man Group plc trimmed | 138,587 | $11M | 0.2% | 2025-Q3 stale |
| FIL Ltd added | 113,966 | $11M | 0.2% | 2025-Q1 stale |
| Divisadero Street Capital Management, LP added | 101,791 | $11M | 0.2% | 2025-Q2 stale |
| GREAT LAKES ADVISORS, LLC trimmed | 106,200 | $10M | 0.2% | 2025-Q1 stale |
| Defilade Capital Management, L.P. new | 91,703 | $10M | 0.2% | 2025-Q4 stale |
| Balyasny Asset Management L.P. added | 87,171 | $10M | 0.1% | 2025-Q4 stale |
| TWO SIGMA ADVISERS, LP added | 69,000 | $8M | 0.1% | 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.