Upstream Bio, Inc. — Director's Dealing 2024

Dec 17, 2024

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Upstream Bio, Inc. (UPB)
CIK: 0002022626
Period of Report: 2024-12-16

Reporting Person: Ambrose Allison (N/A)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2024-12-16	Stock Option (Right to Buy)	$19.01	A	100000	Acquired	2034-12-15	Common Stock (100000)	Direct

Footnotes

F1: 25% of the shares underlying this option shall vest on December 16, 2025, with the remainder vesting in thirty-six equal monthly installments thereafter, subject to the Reporting Person's continued service on such vesting date.