Upstream Bio director granted 17,096 stock options

Upstream Bio, Inc. director Liam Ratcliffe reported receiving a grant of stock options.

Rhea-AI Filing Summary

Upstream Bio, Inc. director Liam Ratcliffe reported receiving a grant of stock options. The award covers 17,096 options to buy common stock at an exercise price of $6.69 per share, expiring on June 8, 2036. Following this grant, he holds 17,096 derivative securities of this type directly.

According to the terms, the shares underlying this option will vest in full on the earlier of June 9, 2027 or the date of the company’s next Annual Meeting of Stockholders, provided he continues serving through the vesting date. This is a compensation-related grant rather than an open-market purchase or sale.

Insider Trade Summary

Grant/Award: 17,096 shares

Grant/Award 1 txn

Insider Ratcliffe Liam

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	17,096	$0.00	$0.00

Holdings After Transaction: Stock Option (Right to Buy) — 17,096 contracts (Direct)

Footnotes (1)

1. F1. The shares underlying this option shall vest in full upon the earlier of (i) June 9, 2027 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.

Key Figures

Option grant size: 17,096 options Exercise price: $6.69 per share Expiration date: June 8, 2036 +3 more

6 metrics

Option grant size 17,096 options Stock Option (Right to Buy) awarded to director

Exercise price $6.69 per share Conversion or exercise price of option grant

Expiration date June 8, 2036 Option term end date

Underlying shares 17,096 shares Common stock underlying the option grant

Holdings after grant 17,096 derivative securities Total options of this award held directly after transaction

Vesting date trigger June 9, 2027 Latest vesting date, or earlier at next annual meeting

Key Terms

Stock Option (Right to Buy), vesting, Annual Meeting of Stockholders, Grant, award, or other acquisition

4 terms

Stock Option (Right to Buy) financial

"Stock Option (Right to Buy)"

vesting financial

"The shares underlying this option shall vest in full upon the earlier"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

Annual Meeting of Stockholders financial

"the date of the next Annual Meeting of Stockholders of the Issuer"

Grant, award, or other acquisition financial

"transaction_code_description: Grant, award, or other acquisition"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Upstream Bio (UPB) director Liam Ratcliffe report in this Form 4?

He reported receiving a grant of 17,096 stock options to buy Upstream Bio common stock at an exercise price of $6.69 per share, expiring on June 8, 2036, as part of his director compensation.

Is the Upstream Bio (UPB) Form 4 transaction a buy or a grant?

The transaction is a grant of stock options, not an open-market share purchase or sale. It is coded as an acquisition under a compensation award, giving the director the right to buy shares at $6.69 per share in the future.

When do Liam Ratcliffe’s Upstream Bio (UPB) options vest?

The options vest in full on the earlier of June 9, 2027 or the date of Upstream Bio’s next Annual Meeting of Stockholders, assuming Liam Ratcliffe continues his service as a director through that vesting date.

How many Upstream Bio (UPB) derivative securities does Liam Ratcliffe hold after this grant?

After this transaction, he holds 17,096 derivative securities of this option award directly. These represent rights to acquire an equal number of Upstream Bio common shares at an exercise price of $6.69 per share before expiration.

Does this Upstream Bio (UPB) Form 4 indicate any stock sales by the director?

No, the filing shows no stock sales. It reports only a grant of stock options as compensation, with 0% of the reported shares classified as sales or tax-withholding dispositions in the transaction summary data.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/11/2026 - 08:00 PM Learn about SEC filing dates

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^*

Ratcliffe Liam

(Last) (First) (Middle)

UPSTREAM BIO, INC.

890 WINTER STREET, SUITE 200

(Street)

WALTHAM MASSACHUSETTS 02451

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/09/2026

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

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

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

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

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)	$6.69	06/09/2026		A		17,096		(1)	06/08/2036	Common Stock	17,096	$0	17,096	D

Explanation of Responses:

1. The shares underlying this option shall vest in full upon the earlier of (i) June 9, 2027 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.

	/s/ Allison Ambrose, Attorney-in-Fact	06/11/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)