Cytek Biosciences (CTKB) director converts 6,107 RSUs into common stock

Rhea-AI Filing Summary

Cytek Biosciences director Richard Chin exercised restricted stock units into common shares. On this date, 6,107 Restricted Stock Units converted into 6,107 shares of common stock at no exercise price. After the transaction, he directly holds 16,285 shares of common stock and 57,004 Restricted Stock Units.

The footnotes explain that each RSU represents a contingent right to one share of common stock and describe a multi‑date vesting schedule, with portions of the award vesting on specified dates in August, November, March, and May until fully vested.

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^*

Chin Richard

(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
	Officer (give title below)		Other (specify below)

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		6,107	A	(1)	16,285	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)	03/10/2026		M			6,107	(2)	(2)	Common Stock	6,107	$0	57,004	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, 2025; 3/36 of the total shares subject to the RSU Award shall vest on November 18, 2025 and each November 18 thereafter; 3/36 of the total shares underlying the RSU Award shall vest on March 10, 2026 and each March 10 thereafter; 3/36 of the total shares underlying the RSU Award vesting shall vest on May 18, 2026 and each May 18 thereafter; and 3/36 of the total shares underlying the RSU Award shall vest on August 18, 2026 and each August 18 thereafter, until fully vested.

	/s/ Valerie Barnett, Attorney-in-Fact	03/12/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Cytek Biosciences (CTKB) director Richard Chin report?

Richard Chin reported exercising 6,107 Restricted Stock Units into 6,107 shares of common stock at no exercise price. This is a derivative exercise, not an open-market purchase or sale, and reflects equity compensation converting into direct share ownership.

How many Cytek Biosciences (CTKB) shares does Richard Chin hold after this Form 4?

Following the reported transaction, Richard Chin directly holds 16,285 shares of Cytek Biosciences common stock. He also holds 57,004 Restricted Stock Units, which represent additional potential shares subject to future vesting under the company’s RSU award terms.

Was Richard Chin’s Cytek Biosciences (CTKB) Form 4 a buy or a sell?

The Form 4 shows an acquisition through derivative exercise, not a market buy or sell. Restricted Stock Units converted into common stock at a zero exercise price, so no open-market transaction or cash purchase or sale is reported here.

What type of security did Richard Chin exercise into Cytek Biosciences (CTKB) common stock?

He exercised Restricted Stock Units, which are equity awards that convert into common shares upon vesting. Each RSU represents a contingent right to receive one share of Cytek Biosciences common stock, according to the footnote description in the filing.

How many Restricted Stock Units does Richard Chin have in Cytek Biosciences (CTKB) after the transaction?

After the transaction, Richard Chin holds 57,004 Restricted Stock Units. These RSUs are scheduled to vest in tranches on specified dates in August, November, March, and May, continuing until the entire RSU award becomes fully vested over time.

Does Richard Chin’s Cytek Biosciences (CTKB) Form 4 indicate any tax withholding or sales?

The summary data show no reported tax withholding or sale transactions associated with this Form 4. The activity consists of a derivative exercise of 6,107 Restricted Stock Units into 6,107 common shares, with no open-market sales or tax-withholding disposals listed.