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Cytek Biosciences (CTKB) CEO gets 120K shares, surrenders some for taxes

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Cytek Biosciences, Inc. (CTKB) reported that President and CEO Wenbin Jiang exercised Restricted Stock Units into common stock on August 18, 2026. Four RSU vesting events resulted in the issuance of 120,095 shares of common stock. To cover related tax withholding obligations, 36,269 shares of common stock were withheld and surrendered at $4.67 per share. The RSU awards vest over four-year schedules with specified portions vesting each May 18, August 18, November 18, and March 10.

Positive

  • None.

Negative

  • None.
Insider Jiang Wenbin
Role PRESIDENT AND CEO
Type Security Shares Price Value
Exercise Restricted Stock Units F1, F3 11,781 $0.00 $0.00
Exercise Restricted Stock Units F1, F4 22,100 $0.00 $0.00
Exercise Restricted Stock Units F1, F5 29,002 $0.00 $0.00
Exercise Restricted Stock Units F1, F6 57,212 $0.00 $0.00
Exercise Common Stock F1 11,781 -- --
Tax Withholding Common Stock F2 2,869 $4.67 $13K
Exercise Common Stock F1 22,100 -- --
Tax Withholding Common Stock F2 5,382 $4.67 $25K
Exercise Common Stock F1 29,002 -- --
Tax Withholding Common Stock F2 7,062 $4.67 $33K
Exercise Common Stock F1 57,212 -- --
Tax Withholding Common Stock F2 20,956 $4.67 $98K
Holdings After Transaction: Restricted Stock Units — 1,287,215 shares (Direct); Common Stock — 5,561,029 shares (Direct)
Footnotes (6)
  1. F1. Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock.
  2. F2. Represents the number of shares withheld by and surrendered to the Issuer on August 18, 2026 to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.
  3. F3. The shares underlying 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.
  4. F4. The shares underlying 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.
  5. F5. The shares underlying 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.
  6. F6. The shares underlying 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 on August 18, 2026 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on 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.
RSU-derived common shares 120,095 shares Total shares from four RSU exercises/conversions on August 18, 2026
Shares withheld for taxes 36,269 shares Shares surrendered to satisfy tax withholding obligations on August 18, 2026
Tax withholding price $4.67 per share Price applied to Form 4 code F tax-withholding transactions
RSU exercises count 4 transactions Number of derivative (RSU) exercise/conversion transactions reported
Tax-withholding transactions count 4 transactions Number of code F transactions for payment of tax liability
Restricted Stock Units financial
"Each Restricted Stock Unit (the "RSU Award") represents a contingent right"
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.
tax withholding obligations financial
"satisfy tax withholding obligations that arose in connection with the vesting"
vest over 4 years financial
"The shares underlying the RSU Award shall vest over 4 years, with 2/48"
Payment of tax liability by delivering or withholding securities financial
"transaction_code_description":"Payment of tax liability by delivering or withholding"

FAQ

What insider transactions did CTKB CEO Wenbin Jiang report on August 18, 2026?
Wenbin Jiang reported vesting and exercise of several RSU awards into 120,095 shares of Cytek Biosciences common stock on August 18, 2026, along with share-withholding transactions to cover associated tax obligations.

How many Cytek Biosciences (CTKB) shares were issued from RSU vesting for the CEO?
RSU vesting and exercises for CEO Wenbin Jiang resulted in the issuance of 120,095 shares of Cytek Biosciences common stock, according to the Form 4 transactions classified as exercises or conversions of derivative securities.

How many CTKB shares were withheld to pay taxes on the CEO’s RSU vesting?
A total of 36,269 shares of Cytek Biosciences common stock were withheld and surrendered on August 18, 2026 to satisfy tax withholding obligations arising from the vesting of the RSU awards, at a price of $4.67 per share.

What price per share was used for the CTKB tax withholding transactions?
The tax-withholding transactions for Wenbin Jiang’s RSU vesting used a per-share price of $4.67 for Cytek Biosciences common stock, applied to the 36,269 shares withheld to satisfy tax obligations.

How do Wenbin Jiang’s RSU awards in CTKB vest over time?
The RSU awards vest over 4-year schedules. Each award vests in installments of 2/48 of the total shares each May 18, 3/48 each August 18, 3/48 each November 18, and 4/48 each March 10, beginning on award-specific start dates from 2023 to 2026.

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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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*
Jiang Wenbin
(Last)(First)(Middle)
C/O CYTEK BIOSCIENCES, INC.
47215 LAKEVIEW BOULEVARD
(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)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
PRESIDENT AND CEO
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
08/18/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock08/18/2026M11,781A(1)5,488,984D
Common Stock08/18/2026F2,869(2)D$4.675,486,115D
Common Stock08/18/2026M22,100A(1)5,508,215D
Common Stock08/18/2026F5,382(2)D$4.675,502,833D
Common Stock08/18/2026M29,002A(1)5,531,835D
Common Stock08/18/2026F7,062(2)D$4.675,524,773D
Common Stock08/18/2026M57,212A(1)5,581,985D
Common Stock08/18/2026F20,956(2)D$4.675,561,029D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Units(1)08/18/2026M11,781 (3) (3)Common Stock11,781$027,494D
Restricted Stock Units(1)08/18/2026M22,100 (4) (4)Common Stock22,100$0139,973D
Restricted Stock Units(1)08/18/2026M29,002 (5) (5)Common Stock29,002$0299,694D
Restricted Stock Units(1)08/18/2026M57,212 (6) (6)Common Stock57,212$0820,054D
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, 2026 to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.
3. The shares underlying 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.
4. The shares underlying 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.
5. The shares underlying 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.
6. The shares underlying 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 on August 18, 2026 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on 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.
/s/ Gordon Ho, Attorney-in-Fact08/20/2026
** Signature of Reporting PersonDate
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