Ambrose Allison 4
4 · Upstream Bio, Inc. · Filed Jun 17, 2026
Research Summary
AI-generated summary of this filing
Upstream Bio (UPB) General Counsel Ambrose Allison Sells Shares
What Happened Ambrose Allison, General Counsel of Upstream Bio, sold 477 shares on 2026-06-16 at $6.10 per share, generating $2,910 of proceeds. The filing classifies the transaction as a sale and notes the shares were sold to satisfy tax withholding obligations tied to the vesting of restricted stock units.
Key Details
- Transaction date: 2026-06-16
- Transaction type/code: Sale (S) — open market or private sale
- Price per share: $6.10; shares sold: 477; proceeds: $2,910
- Shares owned after transaction: Not disclosed in the supplied filing
- Footnote: The sale was an automatic "sell-to-cover" to satisfy tax withholding on RSU vesting (automatic, not at the reporting person's discretion)
- Filing date: 2026-06-17 — filed promptly (Form 4 is generally due within two business days)
Context Sell-to-cover transactions are routine administrative sales to cover tax on vested awards and do not necessarily reflect an insider's view of the company. The size of this sale is small; retail investors typically view purchases as a stronger signal than routine withholding sales.
Insider Transaction Report
Form 4
Ambrose Allison
General Counsel
Transactions
- Sale
Common Stock
[F1]2026-06-16$6.10/sh−477$2,910→ 16,048 total
Footnotes (1)
- [F1]The Issuer has adopted a "sell-to-cover" policy to satisfy the tax withholding obligations of the Reporting Person. The sales reported on this Form 4 represent the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. Such sales were automatic and not at the discretion of the Reporting Person.
Signature
/s/ Allison Ambrose|2026-06-17