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

Rhea-AI Filing Summary

Valerie Barnett, Chief Legal Officer of Cytek Biosciences (CTKB), reported multiple transactions on August 18, 2025 related to restricted stock units (RSUs) that vested. The filing shows vesting and issuance of RSUs in several tranches: 2,016; 3,681; 7,735; and 10,875 units. Shares were withheld to cover tax obligations: 786, 1,434, 3,000 and 3,609 shares respectively. After the reported transactions, Barnett beneficially owned 155,888 shares of common stock.

Positive

• Officer alignment with shareholders: Multiple RSU awards vested, increasing the reporting person's beneficial ownership to 155,888 shares.
• Transparent vesting schedule: Filing discloses detailed vesting timelines for each RSU tranche, clarifying future share issuances.

Negative

• Share withholding for taxes: The issuer withheld a total of 9,829 shares across tranches to satisfy tax obligations, which reduces net shares delivered to the officer.
• No open-market purchases reported: The transactions are compensation-related vesting, not purchases that would indicate additional capital commitment by the officer.

Insights

Corporate Governance Expert

TL;DR: Routine officer RSU vesting and tax withholding; increases vested ownership without indicating new cash purchases.

The Form 4 discloses scheduled vesting of multiple RSU awards for the Chief Legal Officer with corresponding share-withholdings to satisfy tax obligations. These are typical equity compensation mechanics that increase the reporting person's direct beneficial ownership while reducing net share issuance to the officer through withholding. There is no indication of open-market purchases or sales, no derivative exercises for cash, and no change in control or extraordinary corporate action disclosed. The transactions appear administrative and not likely to be material to investors on their own.

Securities Analyst

TL;DR: Incremental ownership change from vested RSUs; impact on float and dilution is minimal and expected.

The aggregated vesting increased reported beneficial ownership to 155,888 shares. Withholdings of 9,829 shares in aggregate satisfied tax obligations, which reduces net new shares delivered to the officer but does not signal trading intent. The filing contains clear vesting schedules and zero exercise prices for the RSUs (they convert into common stock). No sales or market disposals were reported, so this reflects compensation vesting rather than liquidity events.

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
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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^*

Barnett Valerie

(Last) (First) (Middle)

C/O CYTEK BIOSCIENCES, INC.

47215 LAKEVIEW BOULEVARD

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
08/18/2025

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	08/18/2025		M		2,016	A	(1)	85,689	D
Common Stock	08/18/2025		F		786(2)	D	$4.06	84,903	D
Common Stock	08/18/2025		M		3,681	A	(1)	88,584	D
Common Stock	08/18/2025		F		1,434(2)	D	$4.06	87,150	D
Common Stock	08/18/2025		M		7,735	A	(1)	94,885	D
Common Stock	08/18/2025		F		3,000(2)	D	$4.06	91,885	D
Common Stock	08/18/2025		M		10,875	A	(1)	102,760	D
Common Stock	08/18/2025		F		3,609(2)	D	$4.06	99,151	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)	08/18/2025		M			2,016	(3)	(3)	Common Stock	2,016	$0	3,362	D
Restricted Stock Units	(1)	08/18/2025		M			3,681	(4)	(4)	Common Stock	3,681	$0	23,323	D
Restricted Stock Units	(1)	08/18/2025		M			7,735	(5)	(5)	Common Stock	7,735	$0	79,932	D
Restricted Stock Units	(1)	08/18/2025		M			10,875	(6)	(6)	Common Stock	10,875	$0	155,888	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. Represents the number of shares withheld by and surrendered to the Issuer on August 18, 2025, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.

3. The shares subject to the RSU Award shall vest quarterly over four years, with 4/48th of the total shares underlying the RSU Award vesting on May 18, 2022 and 3/48th of the total shares underlying the RSU Award vesting each subsequent quarter thereafter on August 18, November 18, February 18 and May 18.

4. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2023 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2023 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2023 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2024 and each March 10 thereafter, until fully vested.

5. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2024 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2024 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2024 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2025 and each March 10 thereafter.

6. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2025 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2025 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2025 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2026 and each March 10 thereafter, until fully vested.

	/s/ Valerie Barnett	08/20/2025
	** 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).
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FAQ

What transactions did Valerie Barnett report for Cytek Biosciences (CTKB)?

On 08/18/2025, Barnett reported vesting of RSU awards totaling 24,307 shares issued across four tranches (2,016; 3,681; 7,735; 10,875) with tax withholding of 786; 1,434; 3,000; and 3,609 shares respectively.

How many shares does Valerie Barnett beneficially own after these transactions?

The Form 4 reports that Barnett beneficially owns 155,888 shares of Cytek Biosciences common stock following the reported transactions.

Were any shares sold or purchased on the open market in this Form 4?

No. The transactions reported are RSU vestings and share-withholdings for taxes; there are no open-market purchases or sales disclosed.

What does the price column ($4.06) relate to in the filing?

The $4.06 price shown corresponds to the per-share value used for shares surrendered to the issuer to satisfy tax withholding obligations on the vested RSUs.

Do the RSUs have an exercise price?

The RSUs convert to common stock with an effective price of $0; they represent contingent rights to receive shares upon vesting.