Form 4 for CTKB Cytek Biosciences, Inc.
Accepted 2026-08-20 16:22:56 ET · period of report 2026-08-18 · accession 0001874041-26-000009 · 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 | 2026-08-20 16:22 | 2026-08-18 | CTKB | Yan Ming | CTO, Dir | M - OptEx | — | +33.3K | 4.83M | +0.7% | — |
| DM | 2026-08-20 16:22 | 2026-08-18 | CTKB | Yan Ming | CTO, Dir | F - Tax | $4.67 | -8,088 | 4.82M | -0.2% | -$37.8K |
| DM | 2026-08-20 16:22 | 2026-08-18 | CTKB | Yan Ming | CTO, Dir | M - OptEx | $0.00 | -33.3K | 203.8K | -14% | $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 | 2026-08-18 | M | A | 7,363 | — | 4,804,051 | 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 | 2026-08-18 | F | D | 1,778 | $4.67 | 4,802,273 | D | — | — | (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 | Common | Common Stock | 2026-08-18 | M | A | 5,525 | — | 4,807,798 | 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 | 2026-08-18 | F | D | 1,346 | $4.67 | 4,806,452 | D | — | — | (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. |
| 5 | Common | Common Stock | 2026-08-18 | M | A | 6,162 | — | 4,812,614 | 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 | 2026-08-18 | F | D | 1,501 | $4.67 | 4,811,113 | D | — | — | (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. |
| 7 | Common | Common Stock | 2026-08-18 | M | A | 14,220 | — | 4,825,333 | 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 | 2026-08-18 | F | D | 3,463 | $4.67 | 4,821,870 | D | — | — | (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. |
| 9 | Derivative | Restricted Stock Units | 2026-08-18 | M | D | 7,363 | $0.00 | 17,189 | D | — · — to — | 7,363 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 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. (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. |
| 10 | Derivative | Restricted Stock Units | 2026-08-18 | M | D | 5,525 | $0.00 | 34,995 | D | — · — to — | 5,525 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 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. (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. |
| 11 | Derivative | Restricted Stock Units | 2026-08-18 | M | D | 6,162 | $0.00 | 63,688 | D | — · — to — | 6,162 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 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. (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. |
| 12 | Derivative | Restricted Stock Units | 2026-08-18 | M | D | 14,220 | $0.00 | 203,835 | D | — · — to — | 14,220 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 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. (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. |