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Institutional Ownership · SEC Form 13F

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.

336
Institutional holders
57,476,446
Shares held (tracked funds)
99.9%
Of shares outstanding

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).

FundSharesReported value% of valueQuarter
BlackRock, Inc. trimmed8,007,326$862M12.6%2026-Q1
JANUS HENDERSON GROUP PLC added5,348,395$576M8.4%2026-Q1
PRIMECAP MANAGEMENT CO/CA/ trimmed3,370,628$363M5.3%2026-Q1
VANGUARD PORTFOLIO MANAGEMENT LLC new3,208,363$345M5.0%2026-Q1
VANGUARD CAPITAL MANAGEMENT LLC new2,508,771$270M3.9%2026-Q1
STATE STREET CORP added2,182,617$235M3.4%2026-Q1
AMERIPRISE FINANCIAL INC trimmed1,610,774$173M2.5%2026-Q1
ALLIANCEBERNSTEIN L.P. trimmed1,397,556$158M2.3%2026-Q1
CITADEL ADVISORS LLC added1,446,926$156M2.3%2026-Q1
Holocene Advisors, LP added1,383,715$149M2.2%2026-Q1
GOLDMAN SACHS GROUP INC added1,374,958$148M2.2%2026-Q1
GEODE CAPITAL MANAGEMENT, LLC added1,356,453$146M2.1%2026-Q1
MILLENNIUM MANAGEMENT LLC trimmed1,173,696$126M1.8%2026-Q1
WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC trimmed1,073,819$116M1.7%2026-Q1
Capital World Investors added989,060$106M1.6%2026-Q1
Invesco Ltd. added867,363$93M1.4%2026-Q1
BRAIDWELL LP trimmed763,505$82M1.2%2026-Q1
CHARLES SCHWAB INVESTMENT MANAGEMENT INC added714,389$77M1.1%2026-Q1
MORGAN STANLEY added678,825$73M1.1%2026-Q1
BANK OF AMERICA CORP /DE/ added657,432$71M1.0%2026-Q1
NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed612,063$66M1.0%2026-Q1
Artisan Partners Limited Partnership trimmed607,462$65M1.0%2026-Q1
NORGES BANK added654,931$64M0.9%2026-Q1
NORTHERN TRUST CORP trimmed576,209$62M0.9%2026-Q1
Driehaus Capital Management LLC trimmed487,912$53M0.8%2026-Q1
JENNISON ASSOCIATES LLC added487,020$52M0.8%2026-Q1
WESTFIELD CAPITAL MANAGEMENT CO LP trimmed482,219$52M0.8%2026-Q1
RIVERBRIDGE PARTNERS LLC trimmed433,228$47M0.7%2026-Q1
LOOMIS SAYLES & CO L P trimmed421,240$45M0.7%2026-Q1
Allspring Global Investments Holdings, LLC added393,831$44M0.6%2026-Q1
Nuveen, LLC trimmed398,329$43M0.6%2026-Q1
VANGUARD FIDUCIARY TRUST CO new396,719$43M0.6%2026-Q1
UBS Group AG trimmed386,400$42M0.6%2026-Q1
Capital International Investors trimmed373,343$40M0.6%2026-Q1
Bank of New York Mellon Corp trimmed343,173$37M0.5%2026-Q1
PRICE T ROWE ASSOCIATES INC /MD/ added336,425$36M0.5%2026-Q1
Champlain Investment Partners, LLC trimmed319,027$34M0.5%2026-Q1
JPMORGAN CHASE & CO trimmed323,819$34M0.5%2026-Q1
Clearbridge Investments, LLC added286,051$31M0.4%2026-Q1
PRINCIPAL FINANCIAL GROUP INC added280,737$30M0.4%2026-Q1
FMR LLC added264,906$29M0.4%2026-Q1
D. E. Shaw & Co., Inc. trimmed251,176$27M0.4%2026-Q1
BROWN CAPITAL MANAGEMENT LLC trimmed230,028$25M0.4%2026-Q1
PFM Health Sciences, LP added215,685$23M0.3%2026-Q1
C WorldWide Group Holding A/S207,212$22M0.3%2026-Q1
Public Sector Pension Investment Board added205,484$22M0.3%2026-Q1
ROYAL BANK OF CANADA added204,153$22M0.3%2026-Q1
DIMENSIONAL FUND ADVISORS LP trimmed199,084$21M0.3%2026-Q1
ExodusPoint Capital Management, LP added179,728$19M0.3%2026-Q1
Integral Health Asset Management, LLC trimmed175,000$19M0.3%2026-Q1
SEI INVESTMENTS CO trimmed161,680$17M0.3%2026-Q1
Legal & General Group Plc trimmed160,542$17M0.3%2026-Q1
RHUMBLINE ADVISERS added154,176$17M0.2%2026-Q1
GILDER GAGNON HOWE & CO LLC trimmed152,897$16M0.2%2026-Q1
EVENTIDE ASSET MANAGEMENT, LLC trimmed150,036$16M0.2%2026-Q1
NEUBERGER BERMAN GROUP LLC added147,894$16M0.2%2026-Q1
Bellevue Group AG trimmed145,703$16M0.2%2026-Q1
KEYBANK NATIONAL ASSOCIATION/OH added145,270$16M0.2%2026-Q1
WELLINGTON MANAGEMENT GROUP LLP trimmed144,372$16M0.2%2026-Q1
UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added143,774$15M0.2%2026-Q1
AustralianSuper Pty Ltd trimmed131,535$14M0.2%2026-Q1
SILVERCREST ASSET MANAGEMENT GROUP LLC added128,294$14M0.2%2026-Q1
SEGALL BRYANT & HAMILL, LLC trimmed124,951$13M0.2%2026-Q1
LORD, ABBETT & CO. LLC trimmed120,214$13M0.2%2026-Q1
RENAISSANCE TECHNOLOGIES LLC added118,892$13M0.2%2026-Q1
FRED ALGER MANAGEMENT, LLC trimmed113,943$12M0.2%2026-Q1
Swiss National Bank added113,600$12M0.2%2026-Q1
Granite Investment Partners, LLC trimmed111,872$12M0.2%2026-Q1
Qube Research & Technologies Ltd trimmed108,863$12M0.2%2026-Q1
Squarepoint Ops LLC trimmed108,049$12M0.2%2026-Q1
Point72 Asset Management, L.P. trimmed101,340$11M0.2%2026-Q1
RAYMOND JAMES FINANCIAL INC trimmed98,226$10M0.2%2026-Q1
OSTERWEIS CAPITAL MANAGEMENT INC trimmed94,863$10M0.1%2026-Q1
BNP PARIBAS ASSET MANAGEMENT Holding S.A. added94,538$10M0.1%2026-Q1
WCM INVESTMENT MANAGEMENT, LLC trimmed93,427$10M0.1%2026-Q1
Universal- Beteiligungs- und Servicegesellschaft mbH added87,752$9M0.1%2026-Q1
Rhenman & Partners Asset Management AB trimmed84,000$9M0.1%2026-Q1
ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed81,878$9M0.1%2026-Q1
ASSETMARK, INC added76,306$8M0.1%2026-Q1
NEW YORK STATE COMMON RETIREMENT FUND trimmed76,257$8M0.1%2026-Q1
VICTORY CAPITAL MANAGEMENT INC trimmed75,985$8M0.1%2026-Q1
VANGUARD GROUP INC trimmed5,933,917$670M9.8%2025-Q4 stale
MACQUARIE GROUP LTD added600,228$49M0.7%2025-Q3 stale
Sofinnova Investments, Inc. trimmed288,128$33M0.5%2025-Q4 stale
Iron Triangle Partners LP added342,804$28M0.4%2025-Q3 stale
JANE STREET GROUP, LLC added307,183$25M0.4%2025-Q3 stale
Freestone Grove Partners LP added263,889$22M0.3%2025-Q3 stale
RTW INVESTMENTS, LP trimmed190,000$19M0.3%2025-Q1 stale
Polar Asset Management Partners Inc. added177,123$18M0.3%2025-Q2 stale
Atika Capital Management LLC trimmed212,400$17M0.3%2025-Q3 stale
PERCEPTIVE ADVISORS LLC added140,000$16M0.2%2025-Q4 stale
First Turn Management, LLC added136,241$13M0.2%2025-Q1 stale
Avidity Partners Management LP trimmed134,000$13M0.2%2025-Q1 stale
Man Group plc trimmed138,587$11M0.2%2025-Q3 stale
FIL Ltd added113,966$11M0.2%2025-Q1 stale
Divisadero Street Capital Management, LP added101,791$11M0.2%2025-Q2 stale
GREAT LAKES ADVISORS, LLC trimmed106,200$10M0.2%2025-Q1 stale
Defilade Capital Management, L.P. new91,703$10M0.2%2025-Q4 stale
Balyasny Asset Management L.P. added87,171$10M0.1%2025-Q4 stale
TWO SIGMA ADVISERS, LP added69,000$8M0.1%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.

HoldersTotal shares

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.

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