SEC Form 4 · accession 0001193125-26-274121
Upstream Bio, Inc. · UPB
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Aaron Deykin
Officer — Chief Medical Officer
Period of report
Jun 16, 2026
Accepted (ET)
Jun 17, 2026 · 4:05 pm EDT
Rule 10b5-1 plan
box not checked
Issuer CIK
0002022626
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common StockF2 | Jun 16, 2026 | S | 895 | $6.10 | D | 33,197 | D |
Table II — derivative securities
No Table II lines on this filing.
Explanation of responses
- F1The 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.
- F2Includes 1,405 shares of Common Stock previously acquired under the Issuer's 2024 Employee Stock Purchase Plan.