Upstream Bio (NASDAQ: UPB) CFO awarded stock grants on Jan. 2 2026

Rhea-AI Filing Summary

Upstream Bio, Inc. reported that its CFO and COO, Michael Gray, received new equity awards on January 2, 2026. He was granted 30,500 shares of Common Stock in the form of restricted stock units (RSUs) at a price of $0 per share, all held as direct ownership after the grant.

The RSUs were granted under the company’s 2024 Stock Option and Incentive Plan and will vest in sixteen equal quarterly installments following January 1, 2026, contingent on his continued service. Gray was also granted a stock option for 91,500 shares of Common Stock with a $27.07 exercise price, which will vest in forty-eight equal monthly installments after January 1, 2026, also subject to continued service.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

GRAY MICHAEL

(Last) (First) (Middle)

UPSTREAM BIO, INC.

890 WINTER STREET, SUITE 200

(Street)

WALTHAM MA 02451

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Upstream Bio, Inc. [ UPB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CFO and COO

3. Date of Earliest Transaction (Month/Day/Year)
01/02/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/02/2026		A(1)		30,500	A	$0	30,500	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$27.07	01/02/2026		A		91,500		(2)	01/01/2036	Common Stock	91,500	$0	91,500	D

Explanation of Responses:

1. Represents restricted stock units ("RSUs") granted pursuant to the Issuer's 2024 Stock Option and Incentive Plan. Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting. The RSUs shall vest in sixteen equal quarterly installments following January 1, 2026, subject to the Reporting Person's continued service on each such vesting date.

2. The shares underlying this option shall vest in forty-eight equal monthly installments following January 1, 2026, subject to the Reporting Person's continued service on each such vesting date.

	/s/ Allison Ambrose, Attorney-in-Fact	01/06/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transaction did UPB report for Michael Gray on January 2, 2026?

Upstream Bio, Inc. reported that CFO and COO Michael Gray received 30,500 RSUs of Common Stock and a stock option for 91,500 shares on January 2, 2026, all held directly.

How many restricted stock units did UPB grant to its CFO and COO?

Upstream Bio, Inc. granted 30,500 restricted stock units (RSUs) of Common Stock to CFO and COO Michael Gray at a price of $0 per share.

What are the vesting terms of Michael Gray’s RSUs at Upstream Bio (UPB)?

The 30,500 RSUs granted to Michael Gray will vest in sixteen equal quarterly installments following January 1, 2026, subject to his continued service on each vesting date.

What stock options were granted to the UPB CFO and what is the exercise price?

Michael Gray received a stock option for 91,500 shares of Upstream Bio Common Stock with a $27.07 exercise price per share, reported as a grant at $0 option price for the transaction itself.

How do Michael Gray’s new stock options at Upstream Bio vest?

The 91,500-share stock option granted to Michael Gray will vest in forty-eight equal monthly installments following January 1, 2026, conditioned on his continued service at each vesting date.

Are Michael Gray’s newly granted UPB equity awards held directly or indirectly?

Both the 30,500 RSUs and the 91,500-share stock option are reported as direct (D) ownership by Michael Gray.