Cytek Biosciences (CTKB) director converts 43,973 RSUs to common stock

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Cytek Biosciences director Jack Ball exercised a vested equity award for 43,973 shares of common stock through conversion of Restricted Stock Units. The RSU award fully vested on June 10, 2026, and after this non‑market, compensation-related transaction he directly holds 86,678 shares of Cytek common stock.

Insider Trade Summary

43,973 shares exercised/converted

Mixed 2 txns

Insider Ball Jack

Role null

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	43,973	$0.00	--
Exercise	Common Stock	43,973	$0.00	--

Holdings After Transaction: Restricted Stock Units — 0 shares (Direct, null); Common Stock — 86,678 shares (Direct, null)

Footnotes (1)

Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. 100% of the shares subject to the RSU Award vested on June 10, 2026.

Key Figures

RSUs converted: 43,973 shares Holding after transaction: 86,678 shares RSU-to-share ratio: 1:1 +2 more

5 metrics

RSUs converted 43,973 shares Restricted Stock Units converted into common stock on June 10, 2026

Holding after transaction 86,678 shares Direct common stock holdings following RSU conversion

RSU-to-share ratio 1:1 Each RSU represents the right to receive one common share

RSU vesting 100% vested All shares under the RSU award vested on June 10, 2026

Exercise price $0.00 per share Stated transaction price per share for RSU conversion

Key Terms

Restricted Stock Units, derivative security, contingent right, vesting

4 terms

Restricted Stock Units financial

"The filing lists "Restricted Stock Units" as a derivative security title."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

derivative security financial

"The transaction code description is "Exercise or conversion of derivative security"."

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

contingent right financial

"Each Restricted Stock Unit represents a contingent right to receive one share."

vesting financial

"100% of the shares subject to the RSU Award vested on June 10, 2026."

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

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Form 4 Insider Transactions: What Each Field Means →

06/12/2026 - 07:34 PM

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^*

Ball Jack

(Last)

(First)

(Middle)

C/O CYTEK BIOSCIENCES, INC.

47215 LAKEVIEW BLVD.

(Street)

FREMONT

CALIFORNIA

94538

(City)

(State)

(Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/10/2026

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

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

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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/10/2026		M		43,973	A	⁽¹⁾	86,678	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Units	⁽¹⁾	06/10/2026		M			43,973	⁽²⁾	⁽²⁾	Common Stock	43,973	$0	0	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. 100% of the shares subject to the RSU Award vested on June 10, 2026.

	/s/ Valerie Barnett, Attorney-in-Fact	06/12/2026
	** 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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did Cytek Biosciences (CTKB) director Jack Ball report?

Jack Ball reported exercising 43,973 Restricted Stock Units into Cytek common stock. This conversion reflects vesting of a prior equity award rather than an open-market purchase or sale, and resulted in an increase in his directly held common stock shares.

How many Cytek Biosciences (CTKB) shares does Jack Ball hold after this filing?

After the June 10, 2026 transaction, Jack Ball directly holds 86,678 shares of Cytek Biosciences common stock. This total reflects the addition of 43,973 shares received from the vesting and conversion of his Restricted Stock Unit award into common stock.

Was Jack Ball’s Cytek Biosciences (CTKB) Form 4 a market buy or sell?

The Form 4 does not report any open-market buy or sell. It shows a derivative exercise where 43,973 Restricted Stock Units were converted into common stock at a stated price of $0.00 per share as a vesting-related, compensation transaction.

What happened to Jack Ball’s Restricted Stock Units in this Cytek Biosciences (CTKB) filing?

The filing shows 43,973 Restricted Stock Units converted into common stock, leaving zero RSUs from that award outstanding. Footnotes state that 100% of the shares subject to the RSU award vested on June 10, 2026, triggering this conversion.

What does the Form 4 reveal about Cytek Biosciences (CTKB) RSU award terms?

The Form 4 states each Restricted Stock Unit represents a contingent right to receive one share of Cytek common stock. It also notes that 100% of the shares subject to Jack Ball’s RSU award vested on June 10, 2026, leading to share delivery.