Erez Chimovits - 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, 16:17:31 UTC
Previous filing
17 Oct 2024
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Chimovits Erez Director UPSTREAM BIO, INC., 890 WINTER STREET, SUITE 200, WALTHAM /s/ Allison Ambrose, Attorney-in-Fact 12 Jun 2025 0001706399

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, F2
* 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.
F2 Pursuant 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.

Remarks:

Exhibit 24.2 - Substitute Power of Attorney