Ambrose Allison 4
4 · Upstream Bio, Inc. · Filed Mar 17, 2026
Research Summary
AI-generated summary of this filing
Upstream Bio (UPB) General Counsel Ambrose Allison Sells 475 Shares
What Happened
Ambrose Allison, General Counsel of Upstream Bio, sold 475 shares on March 16, 2026 at $9.29 per share, for proceeds of about $4,413. The filing lists the transaction as a sale (S), and the company footnote states the sale was an automatic "sell-to-cover" to satisfy tax withholding when restricted stock units vested — not an active discretionary sale.
Key Details
- Transaction date and price: 2026-03-16, 475 shares @ $9.29 each.
- Proceeds: Approximately $4,413.
- Shares owned after transaction: Not disclosed in the provided filing excerpt.
- Footnote: The issuer has a sell-to-cover policy; these shares were sold automatically to cover taxes on vested RSUs (not at the reporting person's discretion).
- Filing timeliness: Report filed 2026-03-17 for the 2026-03-16 transaction — appears timely based on the provided dates.
Context
Sell-to-cover transactions are routine tax-withholding actions tied to equity vesting and generally convey less information about an insider's market view than voluntary open-market purchases. This was a disposition (sale) solely to cover withholding on vested awards, per the filing footnote.
Insider Transaction Report
Form 4
Ambrose Allison
General Counsel
Transactions
- Sale
Common Stock
[F1]2026-03-16$9.29/sh−475$4,413→ 16,525 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|2026-03-17