Form 4 for CTKB Cytek Biosciences, Inc.
Accepted 2026-05-20 17:48:07 ET · period of report 2026-05-18 · accession 0001878824-26-000002 · SEC index · Original document
Summary rows
Aggregated the way they appear in lists: one row per insider, transaction code and security table.
| X | Filed | Traded | Ticker | Insider | Title | Type | Price | Qty | Owned | ΔOwn | Value |
|---|---|---|---|---|---|---|---|---|---|---|---|
| DM | 2026-05-20 17:48 | 2026-05-18 | CTKB | McCombe William D. | CFO | M - OptEx | — | +25.7K | 115.0K | +29% | — |
| DM | 2026-05-20 17:48 | 2026-05-18 | CTKB | McCombe William D. | CFO | F - Tax | $3.55 | -9,229 | 111.2K | -8% | -$32.8K |
| DM | 2026-05-20 17:48 | 2026-05-18 | CTKB | McCombe William D. | CFO | M - OptEx | $0.00 | -25.7K | 246.1K | -9% | $0 |
Purchase Sale Sale after option exercise All abbreviations
Every reported transaction
| # | Table | Security | Date | Code | A/D | Shares | Price | Owned after | Own | Exercise / expiry | Underlying | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Common | Common Stock | 2026-05-18 | M | A | 6,320 | — | 101,007 | D | — | — | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. |
| 2 | Common | Common Stock | 2026-05-18 | F | D | 2,268 | $3.55 | 98,739 | D | — | — | (F2) Represents the number of shares withheld by and surrendered to the Issuer on May 18, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award. |
| 3 | Common | Common Stock | 2026-05-18 | M | A | 8,700 | — | 107,439 | D | — | — | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. |
| 4 | Common | Common Stock | 2026-05-18 | F | D | 3,122 | $3.55 | 104,317 | D | — | — | (F2) Represents the number of shares withheld by and surrendered to the Issuer on May 18, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award. |
| 5 | Common | Common Stock | 2026-05-18 | M | A | 10,699 | — | 115,016 | D | — | — | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. |
| 6 | Common | Common Stock | 2026-05-18 | F | D | 3,839 | $3.55 | 111,177 | D | — | — | (F2) Represents the number of shares withheld by and surrendered to the Issuer on May 18, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award. |
| 7 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 6,320 | $0.00 | 50,569 | D | — · — to — | 6,320 Common Stock | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. (F3) The shares subject to the RSU Award shall vest over 4 years with 12/48 of the total shares underlying the RSU Award vesting on May 18, 2025; 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 3/48 of the total shares underlying the RSU Award vesting on March 10, 2026 and each March 10 thereafter; and 3/48 of the total shares underlying the RSU Award vesting on May 18, 2026 and each May 18 thereafter. (F3) The shares subject to the RSU Award shall vest over 4 years with 12/48 of the total shares underlying the RSU Award vesting on May 18, 2025; 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 3/48 of the total shares underlying the RSU Award vesting on March 10, 2026 and each March 10 thereafter; and 3/48 of the total shares underlying the RSU Award vesting on May 18, 2026 and each May 18 thereafter. |
| 8 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 8,700 | $0.00 | 147,913 | D | — · — to — | 8,700 Common Stock | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. (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, 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. (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, 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. |
| 9 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 10,699 | $0.00 | 246,091 | D | — · — to — | 10,699 Common Stock | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. (F5) 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 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, until fully vested. (F5) 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 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, until fully vested. |