Cytek Biosciences (CTKB) CEO awarded options, RSUs and surrenders shares for taxes

Rhea-AI Filing Summary

Cytek Biosciences President and CEO Wenbin Jiang reported several equity compensation transactions. He was granted an employee stock option for 485,545 shares of common stock at an exercise price of $4.23 per share, vesting monthly over four years, and a new award of 915,407 restricted stock units (RSUs) that also vest over four years on specified May, August, November, and March dates.

On the same date, previously granted RSUs vested and were converted into common stock in tranches of 15,708, 29,467, and 38,669 shares. To satisfy tax withholding obligations from these vestings, 3,825, 7,747, and 9,416 shares of common stock were surrendered back to the company at $4.23 per share. After these transactions, Jiang directly owned 5,422,683 shares of common stock.

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

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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^*

Jiang Wenbin

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/10/2026

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	03/10/2026		M		15,708	A	(1)	5,375,535	D
Common Stock	03/10/2026		F		3,825(2)	D	$4.23	5,371,710	D
Common Stock	03/10/2026		M		29,467	A	(1)	5,401,177	D
Common Stock	03/10/2026		F		7,747(2)	D	$4.23	5,393,430	D
Common Stock	03/10/2026		M		38,669	A	(1)	5,432,099	D
Common Stock	03/10/2026		F		9,416(2)	D	$4.23	5,422,683	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
Employee Stock Option (right to buy)	$4.23	03/10/2026		A		485,545		(3)	03/09/2036	Common Stock	485,545	$0	485,545	D
Restricted Stock Units	(1)	03/10/2026		A		915,407		(4)	(4)	Common Stock	915,407	$0	915,407	D
Restricted Stock Units	(1)	03/10/2026		M			15,708	(5)	(5)	Common Stock	15,708	$0	47,129	D
Restricted Stock Units	(1)	03/10/2026		M			29,467	(6)	(6)	Common Stock	29,467	$0	176,806	D
Restricted Stock Units	(1)	03/10/2026		M			38,669	(7)	(7)	Common Stock	38,669	$0	348,030	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 March 10, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.

3. The shares subject to the stock option shall vest over 4 years with 1/48 of the total shares underlying the stock option vesting on April 10, 2026 and each month thereafter until fully vested.

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, 2026 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting August 18, 2026 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting November 18, 2026 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2027 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, 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.

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, 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.

7. 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, Attorney-in-Fact	03/12/2026
	** Signature of Reporting Person	Date
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FAQ

What did Cytek Biosciences (CTKB) CEO Wenbin Jiang receive in this Form 4 filing?

Wenbin Jiang received a grant of 485,545 stock options and 915,407 restricted stock units. These equity awards vest over multiple years and are typical compensation tools that tie the CEO’s incentives to Cytek Biosciences’ long-term share performance.

How many Cytek Biosciences (CTKB) shares does the CEO hold after these transactions?

After these transactions, Wenbin Jiang directly holds 5,422,683 shares of Cytek Biosciences common stock. This figure reflects RSUs that vested into shares, minus the portion surrendered to the company to cover tax withholding obligations related to those vestings.

Were any Cytek Biosciences (CTKB) shares sold on the open market in this Form 4?

No open-market sales are reported. The only dispositions are 3,825, 7,747, and 9,416 shares surrendered to Cytek Biosciences at $4.23 per share to satisfy tax withholding obligations triggered by RSU vesting, which is a standard non-market mechanism.

How do the new RSU awards for Cytek Biosciences (CTKB) CEO vest over time?

The RSU awards vest over four years on a set schedule each May 18, August 18, November 18, and March 10. Different portions, expressed as 2/48, 3/48, or 4/48 of the total award, vest on those recurring dates until fully vested.

What are the key terms of the Cytek Biosciences (CTKB) CEO’s new stock option grant?

The CEO’s new stock option covers 485,545 shares of Cytek Biosciences common stock with an exercise price of $4.23 per share. The option vests over four years, with 1/48 of the underlying shares vesting each month beginning on April 10, 2026.