Dere Willard H
SEC insider (Form 3/4/5 filer). CIK 0001311569. Director at Seres Therapeutics, Inc. (MCRB) and 3 other issuers. 20 reported Form 4/5 transactions since Sep 2024; latest on Jul 8, 2026. Located in CAMBRIDGE, MA.
Companies Dere Willard H has filed insider reports for
- Seres Therapeutics, Inc. (MCRB): Director
- Metagenomi Therapeutics, Inc. (MGX): Director
- BIOMARIN PHARMACEUTICAL INC (BMRN): Director
- Mersana Therapeutics, Inc. (MRSN): Director
Dere Willard H
CIK: 0001311569
Transaction Breakdown
High conviction signal
Position reduction
Derivative conversions
Compensation grants
Gifts, tax withholding, conversions, dispositions to the issuer and other codes
Discretionary Trading P&L
Holdings
Transaction History (20 total)
- Jul 8, 2026MCRB
Seres Therapeutics, Inc.
AwardDirectStock Option (right to buy)
6.5K shares- - Jun 9, 2026MGX
Metagenomi Therapeutics, Inc.
AwardDirectStock Option (Right to Buy)
21K shares- - Jun 2, 2026BMRN
BIOMARIN PHARMACEUTICAL INC
AwardDirect7.5K shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
2.5K shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
800 shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
544 shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
1K shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
450 shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
368 shares- - Jan 6, 2026MRSN
Mersana Therapeutics, Inc.
DispositionDirectStock Option (right to buy)
125 shares-
| Type | Shares | Price | Ownership | |||
|---|---|---|---|---|---|---|
| Jul 8, 2026 |  MCRB Seres Therapeutics, Inc. | Award Stock Option (right to buy) | 6,500 | - | - | Direct |
| Jun 9, 2026 |  MGX Metagenomi Therapeutics, Inc. | Award Stock Option (Right to Buy) | 21,000 | - | - | Direct |
| Jun 2, 2026 |  BMRN BIOMARIN PHARMACEUTICAL INC | Award | 7,490 | - | $0 | Direct |
| Jan 6, 2026 |  MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 2,460 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 800 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 544 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 1,000 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 450 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 368 | - | - | Direct |
| Jan 6, 2026 | MRSN Mersana Therapeutics, Inc. | Disposition Stock Option (right to buy) | 125 | - | - | Direct |
1-10 of 20 transactions