Philippe Busque - 10 Mar 2026 Form 4 Insider Report for Cytek Biosciences, Inc. (CTKB)

Role
SVP, GLOBAL SALES AND SERVICES
Signature
/s/ Valerie Barnett, Attorney-in-Fact
Issuer symbol
CTKB
Transactions as of
10 Mar 2026
Net transactions value
$0
Form type
4
Filing time
12 Mar 2026, 16:39:06 UTC
Previous filing
20 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Busque Philippe SVP, GLOBAL SALES AND SERVICES C/O CYTEK BIOSCIENCES, INC., 47215 LAKEVIEW BLVD., FREMONT /s/ Valerie Barnett, Attorney-in-Fact 12 Mar 2026 0001991396

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction CTKB Common Stock Options Exercise +2,049 +7.1% 30,951 10 Mar 2026 Direct F1
transaction CTKB Common Stock Tax liability -635 -2.1% $4.23* 30,316 10 Mar 2026 Direct F2
transaction CTKB Common Stock Options Exercise +2,946 +9.7% 33,262 10 Mar 2026 Direct F1
transaction CTKB Common Stock Tax liability -912 -2.7% $4.23* 32,350 10 Mar 2026 Direct F2
transaction CTKB Common Stock Options Exercise +4,833 +15% 37,183 10 Mar 2026 Direct F1
transaction CTKB Common Stock Tax liability -1,496 -4% $4.23* 35,687 10 Mar 2026 Direct F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction CTKB Employee Stock Option (right to buy) Award +70,665 $0.000000* 70,665 10 Mar 2026 Common Stock 70,665 $4.23 Direct F3
transaction CTKB Restricted Stock Units Award +133,226 $0.000000* 133,226 10 Mar 2026 Common Stock 133,226 Direct F1, F4
transaction CTKB Restricted Stock Units Options Exercise -2,049 -24% $0.000000* 6,665 10 Mar 2026 Common Stock 2,049 Direct F1, F5
transaction CTKB Restricted Stock Units Options Exercise -2,946 -14% $0.000000* 17,682 10 Mar 2026 Common Stock 2,946 Direct F1, F6
transaction CTKB Restricted Stock Units Options Exercise -4,833 -10% $0.000000* 43,505 10 Mar 2026 Common Stock 4,833 Direct F1, F7
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock.
F2 Represents the number of shares withheld by and surrendered to the Issuer on March 10, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.
F3 The shares subject to the stock option shall vest over 4 years with 1/48 of the total shares underlying the stock option vesting on April 10, 2026 and each month thereafter until fully vested.
F4 The shares subject to 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 August 18, 2026 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting 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, until fully vested.
F5 The shares subject to the RSU Award shall vest over four years with 13/48 of the total shares underlying the RSU Award vesting on May 18, 2024; 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; 4/48 of the total shares underlying the RSU Award vesting on March 10, 2025 and each March 10 thereafter; and 2/48 of the total shares underlying the RSU Award vesting on May 18, 2025 and each May 18 thereafter.
F6 The shares subject to 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.
F7 The shares subject to 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, until fully vested.