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Institutional Ownership · SEC Form 13F

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.

148
Institutional holders
79M
Shares held (tracked funds)
61.5%
Of shares outstanding

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.

FundSharesReported value% of valueQuarter
BlackRock, Inc. trimmed9,578,643$42M12.1%2026-Q2
MILLENNIUM MANAGEMENT LLC added9,338,010$41M11.8%2026-Q2
Boston Partners added7,660,943$34M9.7%2026-Q2
HHLR ADVISORS, LTD.6,657,030$29M8.4%2026-Q2
Topline Capital Management, LLC trimmed6,283,450$28M8.0%2026-Q2
VANGUARD CAPITAL MANAGEMENT LLC added4,939,597$22M6.3%2026-Q2
GEODE CAPITAL MANAGEMENT, LLC added3,059,573$14M3.9%2026-Q2
DIMENSIONAL FUND ADVISORS LP trimmed2,616,257$12M3.3%2026-Q2
STATE STREET CORP trimmed2,566,121$11M3.3%2026-Q2
GOLDMAN SACHS GROUP INC trimmed2,167,515$10M2.7%2026-Q2
ROYCE & ASSOCIATES LP added2,081,579$9M2.6%2026-Q2
Russell Investments Group, Ltd. added1,511,315$7M1.9%2026-Q2
BANK OF AMERICA CORP /DE/ added1,315,332$6M1.7%2026-Q2
VANGUARD PORTFOLIO MANAGEMENT LLC trimmed1,141,592$5M1.4%2026-Q2
CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed1,073,253$5M1.4%2026-Q2
NORTHERN TRUST CORP trimmed1,003,294$4M1.3%2026-Q2
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added973,833$4M1.2%2026-Q2
JANE STREET GROUP, LLC added906,162$4M1.1%2026-Q2
TUDOR INVESTMENT CORP ET AL added837,913$4M1.1%2026-Q2
AQR CAPITAL MANAGEMENT LLC trimmed813,971$4M1.0%2026-Q2
VANGUARD FIDUCIARY TRUST CO added740,662$3M0.9%2026-Q2
CITADEL ADVISORS LLC added721,470$3M0.9%2026-Q2
MORGAN STANLEY trimmed701,792$3M0.9%2026-Q2
Qube Research & Technologies Ltd added689,821$3M0.9%2026-Q2
SUSQUEHANNA INTERNATIONAL GROUP, LLP added681,705$3M0.9%2026-Q2
D. E. Shaw & Co., Inc. added669,182$3M0.8%2026-Q2
RENAISSANCE TECHNOLOGIES LLC trimmed661,300$3M0.8%2026-Q2
FMR LLC added504,385$2M0.6%2026-Q2
MARSHALL WACE, LLP added441,704$2M0.6%2026-Q2
Point72 Asset Management, L.P. added422,361$2M0.5%2026-Q2
Jain Global LLC new411,465$2M0.5%2026-Q2
Bank of New York Mellon Corp trimmed371,427$2M0.5%2026-Q2
AMERICAN CENTURY COMPANIES INC added292,103$1M0.4%2026-Q2
Nuveen, LLC added289,415$1M0.4%2026-Q2
Connor, Clark & Lunn Investment Management Ltd. added266,938$1M0.3%2026-Q2
JACOBS LEVY EQUITY MANAGEMENT, INC trimmed241,581$1M0.3%2026-Q2
BNP PARIBAS FINANCIAL MARKETS added215,010$952K0.3%2026-Q2
Y-Intercept (Hong Kong) Ltd new193,128$856K0.2%2026-Q2
Invesco Ltd. trimmed185,671$823K0.2%2026-Q2
TWO SIGMA INVESTMENTS, LP added168,218$745K0.2%2026-Q2
Numerai GP LLC added159,465$706K0.2%2026-Q2
FRANKLIN RESOURCES INC added156,061$691K0.2%2026-Q2
RHUMBLINE ADVISERS trimmed153,225$679K0.2%2026-Q2
CenterBook Partners LP trimmed149,180$661K0.2%2026-Q2
Jump Financial, LLC added148,083$656K0.2%2026-Q2
XTX Topco Ltd added142,723$632K0.2%2026-Q2
JPMORGAN CHASE & CO trimmed141,864$616K0.2%2026-Q2
ALLIANCEBERNSTEIN L.P.141,048$616K0.2%2026-Q2
DEUTSCHE BANK AG\ added111,932$496K0.1%2026-Q2
WELLS FARGO & COMPANY/MN added102,704$455K0.1%2026-Q2
PRICE T ROWE ASSOCIATES INC /MD/ added101,198$449K0.1%2026-Q2
IEQ CAPITAL, LLC trimmed90,100$399K0.1%2026-Q2
UBS Group AG trimmed88,914$394K0.1%2026-Q2
PDT Partners, LLC86,869$385K0.1%2026-Q2
Squarepoint Ops LLC added82,776$367K0.1%2026-Q2
Aquatic Capital Management LLC added76,762$340K0.1%2026-Q2
VOYA INVESTMENT MANAGEMENT LLC trimmed74,034$328K0.1%2026-Q2
MetLife Investment Management, LLC added68,692$304K0.1%2026-Q2
Creative Planning trimmed62,555$277K0.1%2026-Q2
Catalyst Funds Management Pty Ltd new62,500$277K0.1%2026-Q2
LOS ANGELES CAPITAL MANAGEMENT LLC added62,160$275K0.1%2026-Q2
WEALTH ENHANCEMENT ADVISORY SERVICES, LLC trimmed61,873$222K0.1%2026-Q2
Quantinno Capital Management LP added56,823$252K0.1%2026-Q2
CITIGROUP INC added56,130$249K0.1%2026-Q2
MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added56,017$248K0.1%2026-Q2
BALYASNY ASSET MANAGEMENT L.P. new54,381$241K0.1%2026-Q2
Louisiana State Employees Retirement System48,800$213K0.1%2026-Q2
PRELUDE CAPITAL MANAGEMENT, LLC added45,259$200K0.1%2026-Q2
Vanguard Global Advisers, LLC45,212$200K0.1%2026-Q2
CANADA PENSION PLAN INVESTMENT BOARD41,300$183K0.1%2026-Q2
Police & Firemen's Retirement System of New Jersey added39,936$177K0.1%2026-Q2
Campbell & CO Investment Adviser LLC new39,333$174K0.0%2026-Q2
ExodusPoint Capital Management, LP trimmed36,140$160K0.0%2026-Q2
R Squared Ltd added35,412$157K0.0%2026-Q2
NEW YORK STATE COMMON RETIREMENT FUND34,922$155K0.0%2026-Q2
STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM34,670$154K0.0%2026-Q2
MANUFACTURERS LIFE INSURANCE COMPANY, THE added33,965$150K0.0%2026-Q2
STRS OHIO added32,000$142K0.0%2026-Q2
Cerity Partners LLC trimmed29,053$129K0.0%2026-Q2
AXQ CAPITAL, LP added28,299$125K0.0%2026-Q2
Focus Partners Wealth trimmed28,205$125K0.0%2026-Q2
MERCER GLOBAL ADVISORS INC /ADV trimmed25,718$114K0.0%2026-Q2
INTECH INVESTMENT MANAGEMENT LLC added25,633$114K0.0%2026-Q2
Arax Advisory Partners added23,786$105K0.0%2026-Q2
PRUDENTIAL FINANCIAL INC trimmed23,260$103K0.0%2026-Q2
EntryPoint Capital, LLC trimmed22,871$101K0.0%2026-Q2
Laurion Capital Management LP new22,263$99K0.0%2026-Q2
Quadrature Capital Ltd added21,420$95K0.0%2026-Q2
BAILARD, INC.19,900$88K0.0%2026-Q2
State of Tennessee, Department of Treasury trimmed19,809$88K0.0%2026-Q2
HSBC HOLDINGS PLC added19,734$86K0.0%2026-Q2
BARCLAYS PLC trimmed19,606$87K0.0%2026-Q2
ProShare Advisors LLC trimmed15,925$71K0.0%2026-Q2
Tower Research Capital LLC (TRC) added15,594$69K0.0%2026-Q2
ALGERT GLOBAL LLC trimmed14,895$66K0.0%2026-Q2
AMERIPRISE FINANCIAL INC trimmed14,126$63K0.0%2026-Q2
Aigen Investment Management, LP trimmed14,029$62K0.0%2026-Q2
NorthCrest Asset Manangement, LLC trimmed13,923$64K0.0%2026-Q2
VICTORY CAPITAL MANAGEMENT INC trimmed13,655$60K0.0%2026-Q2
CAPTRUST FINANCIAL ADVISORS trimmed13,068$58K0.0%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.

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.

Learn how to read institutional ownership