[Form 4] Cytek Biosciences, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Cytek Biosciences (CTKB) filed a Form 4 showing a director’s equity activity. On 11/18/2025, the reporting person acquired 2,181 shares of common stock through the vesting and settlement of restricted stock units, reported with transaction code "M." After this transaction, the person directly owned 12,359 shares of common stock.

The filing also shows activity in derivative securities. On the same date, 2,181 restricted stock units were converted into common stock at an exercise price of $0, leaving 13,819 restricted stock units beneficially owned directly. Each restricted stock unit represents a contingent right to receive one share of Cytek Biosciences common stock, subject to a multi-date vesting schedule.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Holder Michael

(Last) (First) (Middle)

C/O CYTEK BIOSCIENCES, INC.

47215 LAKEVIEW BLVD.

(Street)

FREMONT CA 94538

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cytek Biosciences, Inc. [ CTKB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
11/18/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	11/18/2025		M		2,181	A	(1)	12,359	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(1)	11/18/2025		M			2,181	(2)	(2)	Common Stock	2,181	$0	13,819	D

Explanation of Responses:

1. Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock.

2. 2/36 of the total shares subject to the RSU Award shall vest on August 18, 2024; 3/36 of the total shares subject to the RSU Award shall vest on November 18, 2024 and each November 18 thereafter; 4/36 of the total shares underlying the RSU Award shall vest on March 10, 2025 and each March 10 thereafter; 2/36 of the total shares underlying the RSU Award vesting shall vest on May 18, 2025 and each May 18 thereafter; and 3/36 of the total shares underlying the RSU Award shall vest on August 18, 2025 and each August 18 thereafter, until fully vested.

	/s/ Valerie Barnett, Attorney-in-Fact	11/20/2025
	** Signature of Reporting Person	Date
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 4 (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.

FAQ

What did the Cytek Biosciences (CTKB) Form 4 report on 11/18/2025?

The Form 4 reports that a director of Cytek Biosciences (CTKB) acquired 2,181 shares of common stock on 11/18/2025 via the settlement of restricted stock units, reported with transaction code "M."

How many Cytek Biosciences (CTKB) common shares does the insider own after this transaction?

Following the reported transaction, the insider directly owns 12,359 shares of Cytek Biosciences common stock, as disclosed in the Form 4.

What happened to the restricted stock units in this Cytek Biosciences Form 4?

On 11/18/2025, 2,181 restricted stock units were converted into common stock at an exercise price of $0, leaving the insider with 13,819 restricted stock units beneficially owned directly.

What does each restricted stock unit represent for Cytek Biosciences (CTKB)?

Each restricted stock unit (RSU Award) represents a contingent right to receive one share of Cytek Biosciences common stock, subject to the vesting terms described in the filing.

What is the vesting schedule for the Cytek Biosciences RSU Award mentioned in the Form 4?

The RSU Award vests in tranches: 2/36 of the total shares vest on August 18, 2024; 3/36 vest on November 18, 2024 and each November 18 thereafter; 4/36 vest on March 10, 2025 and each March 10 thereafter; 2/36 vest on May 18, 2025 and each May 18 thereafter; and 3/36 vest on August 18, 2025 and each August 18 thereafter, until fully vested.

What does transaction code "M" mean in the Cytek Biosciences (CTKB) Form 4?

In this Form 4, transaction code "M" indicates the conversion or exercise of derivative securities, here the settlement of restricted stock units into common stock.