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  4. [Form 3] Cytek Biosciences, Inc. Initial Statement of Beneficial Ownership

Cytek Biosciences (CTKB) director Glenn Muir files initial ownership report

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
3

Rhea-AI Filing Summary

Cytek Biosciences, Inc. director Glenn P. Muir filed an initial Form 3 beneficial ownership report. The filing identifies him as a director but shows no share purchases, sales, option exercises, gifts, or restructurings, and no derivative positions or holdings are detailed in the provided data.

Positive

  • None.

Negative

  • None.
Buy transactions 0 transactions Reported in Form 3 transaction summary
Sell transactions 0 transactions Reported in Form 3 transaction summary
Derivative transactions 0 transactions Reported in Form 3 transaction summary
Gift transactions 0 transactions Reported in Form 3 transaction summary
Tax-withholding transactions 0 transactions Reported in Form 3 transaction summary
Form 3 regulatory
"INSIDER FILING DATA (Form 3):"
Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.
reportingPersons regulatory
""reportingPersons": [ { "name": "MUIR GLENN P""
ten_percent_owner regulatory
""is_ten_percent_owner": 0"
transactionSummary financial
""transactionSummary": { "buyCount": 0"
derivativeSummary financial
""derivativeSummary": []"
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SEC Form 3
FORM 3UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0104
Estimated average burden
hours per response:0.5
1. Name and Address of Reporting Person*
MUIR GLENN P
(Last)(First)(Middle)
C/O CYTEK BIOSCIENCES, INC.
47215 LAKEVIEW BOULEVARD
(Street)
FREMONT CALIFORNIA 94538
(City)(State)(Zip)
UNITED STATES
(Country)		2. Date of Event Requiring Statement (Month/Day/Year)
06/10/2026		3. Issuer Name and Ticker or Trading Symbol
Cytek Biosciences, Inc. [ CTKB ]
3a. Foreign Trading Symbol
5. If Amendment, Date of Original Filed (Month/Day/Year)
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
Officer (give title below)Other (specify below)
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)
Table II - Derivative Securities Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4) 2. Date Exercisable and Expiration Date (Month/Day/Year)3. Title and Amount of Securities Underlying Derivative Security (Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 6. Nature of Indirect Beneficial Ownership (Instr. 5)
Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
No securities are beneficially owned.
/s/ Valerie Barnett, Attorney-in-Fact06/12/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What does the Cytek Biosciences (CTKB) Form 3 for Glenn P. Muir show?

The Form 3 identifies Glenn P. Muir as a director of Cytek Biosciences. It reports no share purchases, sales, exercises, gifts, restructurings, or derivative positions in the summarized data, reflecting only his status as a reporting person.

Does the Cytek Biosciences (CTKB) Form 3 report any insider buying or selling?

No insider buying or selling is reported in this Form 3. The transaction summary shows zero buy and zero sell transactions, with net buy/sell direction described as neutral in the available data.

What positions or titles are disclosed for Glenn P. Muir at Cytek Biosciences (CTKB)?

The filing states that Glenn P. Muir is a director of Cytek Biosciences. It does not list him as an officer or ten percent owner, and no additional roles are specified in the provided information.

Are any option exercises or derivative transactions reported in this Cytek Biosciences (CTKB) Form 3?

No derivative transactions are reported in this Form 3. The derivative transaction count and exercise count are both zero, and the derivative summary section is empty in the provided data.

Does the Cytek Biosciences (CTKB) Form 3 include any gifts or tax-withholding share transfers?

The Form 3 shows no gifts or tax-withholding share transfers. Gift count and tax withholding count are both zero, indicating no such non-market movements are disclosed in the summarized information.