Form 4 for CTKB Cytek Biosciences, Inc.
Accepted 2026-05-20 17:45:03 ET · period of report 2026-05-18 · accession 0001873091-26-000004 · 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 17:45 | 2026-05-18 | CTKB | Barnett Valerie | CLO | M - OptEx | — | +24.3K | 153.4K | +19% | — |
| DM | 2026-05-20 17:45 | 2026-05-18 | CTKB | Barnett Valerie | CLO | F - Tax | $3.55 | -8,719 | 150.0K | -5% | -$31.0K |
| DM | 2026-05-20 17:45 | 2026-05-18 | CTKB | Barnett Valerie | CLO | M - OptEx | $0.00 | -24.3K | 217.0K | -10% | $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 | 2,454 | — | 136,890 | 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 | 881 | $3.55 | 136,009 | 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 | 5,156 | — | 141,165 | 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 | 1,850 | $3.55 | 139,315 | 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 | 7,250 | — | 146,565 | 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 | 2,602 | $3.55 | 143,963 | 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 | Common | Common Stock | 2026-05-18 | M | A | 9,435 | — | 153,398 | D | — | — | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. |
| 8 | Common | Common Stock | 2026-05-18 | F | D | 3,386 | $3.55 | 150,012 | 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. |
| 9 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 2,454 | $0.00 | 12,280 | D | — · — to — | 2,454 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 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, until fully vested. (F3) 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, 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, until fully vested. |
| 10 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 5,156 | $0.00 | 56,728 | D | — · — to — | 5,156 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, 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. (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, 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. |
| 11 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 7,250 | $0.00 | 123,262 | D | — · — to — | 7,250 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, 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. (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, 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. |
| 12 | Derivative | Restricted Stock Units | 2026-05-18 | M | D | 9,435 | $0.00 | 217,018 | D | — · — to — | 9,435 Common Stock | (F1) Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock. (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, 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. (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, 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. |