Liam Ratcliffe - 10 Jun 2025 Form 4 Insider Report for Upstream Bio, Inc. (UPB)

Role
Director
Signature
/s/ Allison Ambrose, Attorney-in-Fact
Issuer symbol
UPB
Transactions as of
10 Jun 2025
Net transactions value
$0
Form type
4
Filing time
12 Jun 2025, 16:17:20 UTC
Previous filing
15 Oct 2024
Next filing
13 Jun 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Ratcliffe Liam Director UPSTREAM BIO, INC., 890 WINTER STREET, SUITE 200, WALTHAM /s/ Allison Ambrose, Attorney-in-Fact 12 Jun 2025 0001547100

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction UPB Stock Option (Right to Buy) Award $0 +17,096 $0.000000 17,096 10 Jun 2025 Common Stock 17,096 $11.59 Direct F1
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 The shares underlying this option shall vest upon the earlier of (i) June 10, 2026 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.

Remarks:

Exhibit 24.2 - Substitute Power of Attorney