| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 01/17/2023 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 6.2k | $5.74 | $35.8k | | 01/13/2023 |
| 01/15/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 7.9k | $0.00 | $0 | | 01/13/2023 |
| 01/15/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 7.3k | $0.00 | $0 | | 01/13/2023 |
| 01/14/2023 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted stock unit | 4.8k | $0.00 | $0 | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted stock unit | 37.5k | $0.00 | $0 | | 01/13/2023 |
| 01/13/2023 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock option (right to buy) | 168.8k | $6.06 | $1M | | 01/13/2023 |
| 12/14/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 11.1k | $1.40 | $15.6k | | 12/14/2022 |
| 12/14/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 24.2k | $1.53 | $37.1k | | 12/14/2022 |
| 01/18/2022 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 4.7k | $5.92 | $28.1k | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted Stock Units | 7.9k | $0.00 | $0 | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted Stock Units | 7.3k | $0.00 | $0 | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Stock Option (right to buy) | 86.2k | $6.28 | $541.6k | | 01/14/2022 |
| 01/14/2022 | Mersana Therapeutics, Inc. | MRSN | Grant | Restricted Stock Units | 19.2k | $0.00 | $0 | | 01/14/2022 |
| 12/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 45.6k | $1.40 | $63.8k | | 12/20/2021 |
| 08/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $11.01 | $24.4k | | 08/20/2021 |
| 08/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2.2k | $6.16 | $13.7k | | 08/20/2021 |
| 07/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2.2k | $6.16 | $13.7k | | 07/20/2021 |
| 07/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $12.11 | $27k | | 07/20/2021 |
| 07/19/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 8.5k | $12.02 | $102.1k | | 07/15/2021 |
| 07/16/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 7.8k | $12.47 | $97k | | 07/15/2021 |
| 07/15/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Restricted Stock Units | 40k | $0.00 | $0 | | 07/15/2021 |
| 07/08/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 20k | $1.40 | $28k | | 07/08/2021 |
| 06/21/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2 | $13.78 | $27.6 | | 06/21/2021 |
| 06/21/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $13.78 | $30.6k | | 06/21/2021 |
| 06/21/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2 | $3.51 | $7 | | 06/21/2021 |
| 06/21/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2.2k | $6.16 | $13.7k | | 06/21/2021 |
| 05/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 1.9k | $3.51 | $6.6k | | 05/20/2021 |
| 05/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2.2k | $6.16 | $13.7k | | 05/20/2021 |
| 05/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 1.9k | $14.10 | $26.4k | | 05/20/2021 |
| 05/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $14.10 | $31.4k | | 05/20/2021 |
| 04/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 1.9k | $15.91 | $29.8k | | 04/20/2021 |
| 04/20/2021 | Mersana Therapeutics, Inc. | MRSN | Sale | Common Stock | 2.2k | $15.91 | $35.4k | | 04/20/2021 |
| 04/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 1.9k | $3.51 | $6.6k | | 04/20/2021 |
| 04/20/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 2.2k | $6.16 | $13.7k | | 04/20/2021 |
| 03/22/2021 | Mersana Therapeutics, Inc. | MRSN | Exercise | Stock Option (right to buy) | 1.9k | $3.51 | $6.6k | | 03/22/2021 |
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