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

Rhea-AI Filing Summary

Cytek Biosciences director Michael Holder received a grant of 2,181 Restricted Stock Units (RSUs) reported on Form 4 with a transaction date of 08/18/2025. Each RSU converts to one share of common stock upon vesting; the filing shows these RSUs were reported as acquired at a $0 price and increased the reporting person’s beneficial ownership to 10,178 shares following the transaction. The RSU award vests per a schedule described in the filing, with portions vesting on specified dates (including August 18 and November 18 milestones) over multiple years until fully vested.

Insights

Financial Analyst

TL;DR: Director received 2,181 RSUs, increasing beneficial ownership to 10,178 shares; transaction appears routine compensation-related equity grant.

The Form 4 reports a standard equity award to a director: 2,181 RSUs converting one-for-one into common shares and recorded at a $0 reported price, reflecting a grant rather than an open-market purchase. The filing details a staggered vesting schedule with multiple vesting dates through August 18, 2025 and beyond, which implies the award is intended to retain and align the director with shareholder interests over time. There are no sales or derivative exercises disclosed in this filing, and the change in ownership is modest in absolute terms.

Corporate Governance Expert

TL;DR: This is a governance/compensation disclosure showing a director RSU grant with multi-period vesting; it is procedural and not exceptional.

The disclosure identifies the reporting person as a director and shows the grant follows a defined vesting cadence: fractional portions vest on specific calendar dates (2/36, 3/36, 4/36 allocations across listed dates). That vesting structure is consistent with retention-oriented equity awards. The Form 4 is signed by an attorney-in-fact, indicating proper authorization. No departures, option exercises, or disposals are reported, and the filing does not indicate any contravening arrangements or Rule 10b5-1 plan markings.

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^*

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)
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		2,181	A	$0	10,178	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			2,181	(2)	(2)	Common Stock	2,181	$0	16,000	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	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 transaction did the Form 4 for CTKB report?

The Form 4 reports the acquisition of 2,181 Restricted Stock Units (RSUs) by director Michael Holder on 08/18/2025.

How many shares does the reporting person own after the transaction?

Following the reported transaction the reporting person beneficially owns 10,178 shares of Cytek Biosciences common stock.

What is the vesting schedule for the RSU award disclosed on the Form 4?

The filing states fractional vesting: 2/36 vest on Aug 18, 2024; 3/36 on Nov 18, 2024 and each Nov 18 thereafter; 4/36 on Mar 10, 2025 and each Mar 10 thereafter; 2/36 on May 18, 2025 and each May 18 thereafter; and 3/36 on Aug 18, 2025 and each Aug 18 thereafter until fully vested.

Was any cash paid for the RSUs reported in the Form 4?

No cash was reported; the RSUs were recorded with a price of $0 in the Form 4.

Who signed the Form 4 filing for this transaction?

The Form 4 is signed by Valerie Barnett, Attorney-in-Fact on 08/20/2025.