Form4insider filings, from the source

SEC Form 4 · accession 0001193125-26-268166

Upstream Bio, Inc. · UPB

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owner
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

SecurityConv. / exercise priceDateCodeSharesA/DExercisableExpiresUnderlyingUnderlying sharesOwned afterD/I
Stock Option (Right to Buy)F1$6.69Jun 9, 2026A17,096A—Jun 8, 2036Common Stock17,09617,096D

Explanation of responses