STOCK TITAN

Cytek Biosciences (CTKB) CTO gets 33,270 shares, surrenders some for taxes

(Neutral)
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Cytek Biosciences, Inc. (CTKB) reported that director and Chief Technology Officer Yan Ming had several Restricted Stock Unit ("RSU Award") tranches vest on August 18, 2026, each RSU converting into one share of common stock. In total, 33,270 shares of common stock were acquired through exercises or conversions of RSUs. To cover related tax obligations, 8,088 shares of common stock were withheld and surrendered to Cytek at $4.67 per share. The RSU Awards vest over four-year schedules, with specified fractions of the total shares vesting on May 18, August 18, November 18, and March 10 of each year for the different grants.

Positive

  • None.

Negative

  • None.
Insider Yan Ming
Role CHIEF TECHNOLOGY OFFICER
Type Security Shares Price Value
Exercise Restricted Stock Units F1, F3 7,363 $0.00 $0.00
Exercise Restricted Stock Units F1, F4 5,525 $0.00 $0.00
Exercise Restricted Stock Units F1, F5 6,162 $0.00 $0.00
Exercise Restricted Stock Units F1, F6 14,220 $0.00 $0.00
Exercise Common Stock F1 7,363 -- --
Tax Withholding Common Stock F2 1,778 $4.67 $8K
Exercise Common Stock F1 5,525 -- --
Tax Withholding Common Stock F2 1,346 $4.67 $6K
Exercise Common Stock F1 6,162 -- --
Tax Withholding Common Stock F2 1,501 $4.67 $7K
Exercise Common Stock F1 14,220 -- --
Tax Withholding Common Stock F2 3,463 $4.67 $16K
Holdings After Transaction: Restricted Stock Units — 319,707 shares (Direct); Common Stock — 4,821,870 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.
Shares acquired via RSU vesting 33,270 shares of common stock Total derivative exercises or conversions (RSU Awards) on August 18, 2026
Shares withheld for taxes 8,088 shares of common stock Code F tax-withholding dispositions on August 18, 2026
Tax withholding price $4.67 per share Per-share value for common stock withheld to satisfy tax obligations
RSU exercise count 4 derivative exercises Number of RSU-related exercise or conversion transactions (code M)
RSU vesting term 4 years Each RSU Award vests over four years in scheduled installments
Tax-withholding transactions 4 transactions Code F entries for payment of tax liability by withholding securities
Net buy/sell share impact 0 shares Net buy/sell direction reported as neutral across all transactions
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
"surrendered to the Issuer on August 18, 2026 to satisfy tax withholding obligations"
derivative security financial
"transaction code description: 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.
Payment of tax liability by delivering or withholding securities financial
"transaction code description: Payment of tax liability by delivering or withholding securities"

FAQ

What transactions did Yan Ming report in this Form 4 for CTKB?

Yan Ming reported multiple RSU Award vestings on August 18, 2026, converting into 33,270 shares of Cytek Biosciences common stock, with a portion of shares then withheld to satisfy tax obligations.

How many Cytek Biosciences (CTKB) shares vested from RSUs on August 18, 2026?

On August 18, 2026, RSU Awards for Yan Ming vested into an aggregate of 33,270 shares of Cytek Biosciences common stock, as reflected by the derivative exercise total in the filing.

Were any CTKB shares sold into the market in this Form 4?

The filing shows no open-market purchases or sales. Instead, 8,088 shares of common stock were withheld by and surrendered to Cytek to satisfy tax withholding obligations arising from RSU vesting.

At what price were CTKB shares withheld for taxes?

Shares withheld to satisfy tax obligations were valued at $4.67 per share, which applies to the code F tax-withholding transactions totaling 8,088 shares of common stock.

What is the vesting schedule of Yan Ming’s RSU Awards at Cytek Biosciences (CTKB)?

Each RSU Award vests over 4 years, with portions of the total shares vesting on May 18, August 18, November 18, and March 10 each year, according to detailed 48-part fraction schedules for each grant.

What roles does Yan Ming hold at Cytek Biosciences (CTKB)?

Yan Ming is reported as both a director and an officer of Cytek Biosciences, Inc., serving as Chief Technology Officer.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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*
Yan Ming

(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)
CHIEF TECHNOLOGY OFFICER
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 Stock08/18/2026M7,363A(1)4,804,051D
Common Stock08/18/2026F1,778(2)D$4.674,802,273D
Common Stock08/18/2026M5,525A(1)4,807,798D
Common Stock08/18/2026F1,346(2)D$4.674,806,452D
Common Stock08/18/2026M6,162A(1)4,812,614D
Common Stock08/18/2026F1,501(2)D$4.674,811,113D
Common Stock08/18/2026M14,220A(1)4,825,333D
Common Stock08/18/2026F3,463(2)D$4.674,821,870D
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)08/18/2026M7,363 (3) (3)Common Stock7,363$017,189D
Restricted Stock Units(1)08/18/2026M5,525 (4) (4)Common Stock5,525$034,995D
Restricted Stock Units(1)08/18/2026M6,162 (5) (5)Common Stock6,162$063,688D
Restricted Stock Units(1)08/18/2026M14,220 (6) (6)Common Stock14,220$0203,835D
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)