Upstream Bio, Inc. — Director's Dealing 2024

Oct 16, 2024

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Upstream Bio, Inc. (UPB)
CIK: 0002022626
Period of Report: 2024-10-15

Reporting Person: Wellington Biomedical Innovation Master Investors (Cayman) II L.P. (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2024-10-15	Common Stock	C	894733	—	Acquired	894733	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2024-10-15	Series B redeemable convertible preferred stock	$	C	852940	Disposed		Common Stock (894733)	Direct

Footnotes

F1: Each share of Series B redeemable convertible preferred stock automatically converted into Common Stock on a 1.049-for-one basis upon closing of the Issuer's initial public offering without payment of consideration. The Series B redeemable convertible preferred stock had no expiration date.