SEC Form 4 · accession 0001193125-26-268164
Upstream Bio, Inc. · UPB
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Erez Chimovits
Director
Period of report
Jun 9, 2026
Accepted (ET)
Jun 11, 2026 · 8:00 pm EDT
Rule 10b5-1 plan
box not checked
Issuer CIK
0002022626
Table I — non-derivative securities
No Table I lines on this filing.
Table II — derivative securities
| Security | Conv. / exercise price | Date | Code | Shares | A/D | Exercisable | Expires | Underlying | Underlying shares | Owned after | D/I |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Stock Option (Right to Buy)F2,F1 | $6.69 | Jun 9, 2026 | A | 17,096 | A | — | Jun 8, 2036 | Common Stock | 17,096 | 17,096 | D |
Explanation of responses
- F1The shares underlying this option shall vest in full upon the earlier of (i) June 9, 2027 and (ii) the date of the next Annual Meeting of Stockholders of the Issuer, subject to the Reporting Person's continued service on such vesting date.
- F2Pursuant to an agreement with OrbiMed Advisors LLC, OrbiMed Capital GP VIII LLC, OrbiMed Israel GP II, L.P., and OrbiMed Advisors Israel II Limited, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC, OrbiMed Capital GP VIII LLC, OrbiMed Israel GP II, L.P., and OrbiMed Advisors Israel II Limited, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VIII, LP and OrbiMed Israel Partners II, L.P.