Who owns Cytek Biosciences (CTKB)
Which tracked institutional funds hold CTKB, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See CTKB company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 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
26 tracked funds added or opened CTKB while 22 trimmed or exited it between 2026-Q1 and 2026-Q2 — 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
CTKB’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 CTKB more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in CTKB 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 2026-Q1 and 2026-Q2, across 148 tracked filers holding CTKB, 71 increased or opened the position and 107 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
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 CTKB between the 2026-Q1 and 2026-Q2 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 7
- JANE STREET GROUP, LLC$4M
- Qube Research & Technologies Ltd$3M
- MARSHALL WACE, LLP$2M
- Point72 Asset Management, L.P.$2M
- Jain Global LLC$2M
- Y-Intercept (Hong Kong) Ltd$856K
Full exits 6
- BROWN CAPITAL MANAGEMENT LLC$6M
- Simcoe Capital LLC$4M
- PRINCIPAL FINANCIAL GROUP INC$2M
- HRT FINANCIAL LP$2M
- ACADIAN ASSET MANAGEMENT LLC$2M
- Public Sector Pension Investment Board$2M
Largest adds
- MILLENNIUM MANAGEMENT LLC$14M
- Boston Partners$9M
- ARROWSTREET CAPITAL, LIMITED PARTNERSHIP$3M
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$3M
- TUDOR INVESTMENT CORP ET AL$2M
- ROYCE & ASSOCIATES LP$2M
Largest trims
- BlackRock, Inc.$32M
- STATE STREET CORP$7M
- VANGUARD PORTFOLIO MANAGEMENT LLC$5M
- MORGAN STANLEY$4M
- Topline Capital Management, LLC$3M
- CenterBook Partners LP$3M
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. trimmed | 9,578,643 | $42M | 12.1% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC added | 9,338,010 | $41M | 11.8% | 2026-Q2 |
| Boston Partners added | 7,660,943 | $34M | 9.7% | 2026-Q2 |
| HHLR ADVISORS, LTD. | 6,657,030 | $29M | 8.4% | 2026-Q2 |
| Topline Capital Management, LLC trimmed | 6,283,450 | $28M | 8.0% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 4,939,597 | $22M | 6.3% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 3,059,573 | $14M | 3.9% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 2,616,257 | $12M | 3.3% | 2026-Q2 |
| STATE STREET CORP trimmed | 2,566,121 | $11M | 3.3% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC trimmed | 2,167,515 | $10M | 2.7% | 2026-Q2 |
| ROYCE & ASSOCIATES LP added | 2,081,579 | $9M | 2.6% | 2026-Q2 |
| Russell Investments Group, Ltd. added | 1,511,315 | $7M | 1.9% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 1,315,332 | $6M | 1.7% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC trimmed | 1,141,592 | $5M | 1.4% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 1,073,253 | $5M | 1.4% | 2026-Q2 |
| NORTHERN TRUST CORP trimmed | 1,003,294 | $4M | 1.3% | 2026-Q2 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 973,833 | $4M | 1.2% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 906,162 | $4M | 1.1% | 2026-Q2 |
| TUDOR INVESTMENT CORP ET AL added | 837,913 | $4M | 1.1% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 813,971 | $4M | 1.0% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 740,662 | $3M | 0.9% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 721,470 | $3M | 0.9% | 2026-Q2 |
| MORGAN STANLEY trimmed | 701,792 | $3M | 0.9% | 2026-Q2 |
| Qube Research & Technologies Ltd added | 689,821 | $3M | 0.9% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 681,705 | $3M | 0.9% | 2026-Q2 |
| D. E. Shaw & Co., Inc. added | 669,182 | $3M | 0.8% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 661,300 | $3M | 0.8% | 2026-Q2 |
| FMR LLC added | 504,385 | $2M | 0.6% | 2026-Q2 |
| MARSHALL WACE, LLP added | 441,704 | $2M | 0.6% | 2026-Q2 |
| Point72 Asset Management, L.P. added | 422,361 | $2M | 0.5% | 2026-Q2 |
| Jain Global LLC new | 411,465 | $2M | 0.5% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 371,427 | $2M | 0.5% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC added | 292,103 | $1M | 0.4% | 2026-Q2 |
| Nuveen, LLC added | 289,415 | $1M | 0.4% | 2026-Q2 |
| Connor, Clark & Lunn Investment Management Ltd. added | 266,938 | $1M | 0.3% | 2026-Q2 |
| JACOBS LEVY EQUITY MANAGEMENT, INC trimmed | 241,581 | $1M | 0.3% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 215,010 | $952K | 0.3% | 2026-Q2 |
| Y-Intercept (Hong Kong) Ltd new | 193,128 | $856K | 0.2% | 2026-Q2 |
| Invesco Ltd. trimmed | 185,671 | $823K | 0.2% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 168,218 | $745K | 0.2% | 2026-Q2 |
| Numerai GP LLC added | 159,465 | $706K | 0.2% | 2026-Q2 |
| FRANKLIN RESOURCES INC added | 156,061 | $691K | 0.2% | 2026-Q2 |
| RHUMBLINE ADVISERS trimmed | 153,225 | $679K | 0.2% | 2026-Q2 |
| CenterBook Partners LP trimmed | 149,180 | $661K | 0.2% | 2026-Q2 |
| Jump Financial, LLC added | 148,083 | $656K | 0.2% | 2026-Q2 |
| XTX Topco Ltd added | 142,723 | $632K | 0.2% | 2026-Q2 |
| JPMORGAN CHASE & CO trimmed | 141,864 | $616K | 0.2% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. | 141,048 | $616K | 0.2% | 2026-Q2 |
| DEUTSCHE BANK AG\ added | 111,932 | $496K | 0.1% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 102,704 | $455K | 0.1% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 101,198 | $449K | 0.1% | 2026-Q2 |
| IEQ CAPITAL, LLC trimmed | 90,100 | $399K | 0.1% | 2026-Q2 |
| UBS Group AG trimmed | 88,914 | $394K | 0.1% | 2026-Q2 |
| PDT Partners, LLC | 86,869 | $385K | 0.1% | 2026-Q2 |
| Squarepoint Ops LLC added | 82,776 | $367K | 0.1% | 2026-Q2 |
| Aquatic Capital Management LLC added | 76,762 | $340K | 0.1% | 2026-Q2 |
| VOYA INVESTMENT MANAGEMENT LLC trimmed | 74,034 | $328K | 0.1% | 2026-Q2 |
| MetLife Investment Management, LLC added | 68,692 | $304K | 0.1% | 2026-Q2 |
| Creative Planning trimmed | 62,555 | $277K | 0.1% | 2026-Q2 |
| Catalyst Funds Management Pty Ltd new | 62,500 | $277K | 0.1% | 2026-Q2 |
| LOS ANGELES CAPITAL MANAGEMENT LLC added | 62,160 | $275K | 0.1% | 2026-Q2 |
| WEALTH ENHANCEMENT ADVISORY SERVICES, LLC trimmed | 61,873 | $222K | 0.1% | 2026-Q2 |
| Quantinno Capital Management LP added | 56,823 | $252K | 0.1% | 2026-Q2 |
| CITIGROUP INC added | 56,130 | $249K | 0.1% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 56,017 | $248K | 0.1% | 2026-Q2 |
| BALYASNY ASSET MANAGEMENT L.P. new | 54,381 | $241K | 0.1% | 2026-Q2 |
| Louisiana State Employees Retirement System | 48,800 | $213K | 0.1% | 2026-Q2 |
| PRELUDE CAPITAL MANAGEMENT, LLC added | 45,259 | $200K | 0.1% | 2026-Q2 |
| Vanguard Global Advisers, LLC | 45,212 | $200K | 0.1% | 2026-Q2 |
| CANADA PENSION PLAN INVESTMENT BOARD | 41,300 | $183K | 0.1% | 2026-Q2 |
| Police & Firemen's Retirement System of New Jersey added | 39,936 | $177K | 0.1% | 2026-Q2 |
| Campbell & CO Investment Adviser LLC new | 39,333 | $174K | 0.0% | 2026-Q2 |
| ExodusPoint Capital Management, LP trimmed | 36,140 | $160K | 0.0% | 2026-Q2 |
| R Squared Ltd added | 35,412 | $157K | 0.0% | 2026-Q2 |
| NEW YORK STATE COMMON RETIREMENT FUND | 34,922 | $155K | 0.0% | 2026-Q2 |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM | 34,670 | $154K | 0.0% | 2026-Q2 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE added | 33,965 | $150K | 0.0% | 2026-Q2 |
| STRS OHIO added | 32,000 | $142K | 0.0% | 2026-Q2 |
| Cerity Partners LLC trimmed | 29,053 | $129K | 0.0% | 2026-Q2 |
| AXQ CAPITAL, LP added | 28,299 | $125K | 0.0% | 2026-Q2 |
| Focus Partners Wealth trimmed | 28,205 | $125K | 0.0% | 2026-Q2 |
| MERCER GLOBAL ADVISORS INC /ADV trimmed | 25,718 | $114K | 0.0% | 2026-Q2 |
| INTECH INVESTMENT MANAGEMENT LLC added | 25,633 | $114K | 0.0% | 2026-Q2 |
| Arax Advisory Partners added | 23,786 | $105K | 0.0% | 2026-Q2 |
| PRUDENTIAL FINANCIAL INC trimmed | 23,260 | $103K | 0.0% | 2026-Q2 |
| EntryPoint Capital, LLC trimmed | 22,871 | $101K | 0.0% | 2026-Q2 |
| Laurion Capital Management LP new | 22,263 | $99K | 0.0% | 2026-Q2 |
| Quadrature Capital Ltd added | 21,420 | $95K | 0.0% | 2026-Q2 |
| BAILARD, INC. | 19,900 | $88K | 0.0% | 2026-Q2 |
| State of Tennessee, Department of Treasury trimmed | 19,809 | $88K | 0.0% | 2026-Q2 |
| HSBC HOLDINGS PLC added | 19,734 | $86K | 0.0% | 2026-Q2 |
| BARCLAYS PLC trimmed | 19,606 | $87K | 0.0% | 2026-Q2 |
| ProShare Advisors LLC trimmed | 15,925 | $71K | 0.0% | 2026-Q2 |
| Tower Research Capital LLC (TRC) added | 15,594 | $69K | 0.0% | 2026-Q2 |
| ALGERT GLOBAL LLC trimmed | 14,895 | $66K | 0.0% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC trimmed | 14,126 | $63K | 0.0% | 2026-Q2 |
| Aigen Investment Management, LP trimmed | 14,029 | $62K | 0.0% | 2026-Q2 |
| NorthCrest Asset Manangement, LLC trimmed | 13,923 | $64K | 0.0% | 2026-Q2 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 13,655 | $60K | 0.0% | 2026-Q2 |
| CAPTRUST FINANCIAL ADVISORS trimmed | 13,068 | $58K | 0.0% | 2026-Q2 |
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.