Upstream Bio (UPB) CFO Michael Gray Sells 853 Shares

What Happened
Michael Gray, Chief Financial Officer and Chief Operating Officer of Upstream Bio (UPB), sold 853 shares on 2026-09-16 at $5.49 per share, generating proceeds of $4,683. The sale is reported as a routine disposition tied to tax withholding for the vesting of restricted stock units rather than a discretionary investment sale.

Key Details

• Transaction date: 2026-09-16 (reported on Form 4 filed 2026-09-17).
• Transaction type/code: Sale (S) — open market/private sale to cover taxes.
• Shares sold: 853 at $5.49 each; total proceeds $4,683.
• Shares owned after transaction: Not specified in the provided filing summary.
• Footnote: Issuer’s "sell-to-cover" policy used to satisfy tax withholding; sales were automatic and not at the reporting person's discretion (Footnote F1).
• Filing timeliness: Reported promptly (no late filing indicated).

Context
"Sell-to-cover" transactions are common when restricted stock units vest: enough shares are sold automatically to cover taxes, and do not necessarily reflect the insider’s view of the company’s prospects. The small dollar amount here ($4.7k) suggests this was solely to meet tax obligations rather than a material change in insider ownership.