Upstream Bio (UPB) CEO’s 2,095-share sale tied to RSU tax withholding

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Form Type

Rhea-AI Filing Summary

Upstream Bio, Inc. Chief Executive Officer Everett Rand Sutherland reported an open-market sale of 2,095 shares of common stock at $6.10 per share. According to the filing, these shares were sold automatically under the company’s sell-to-cover policy to satisfy tax withholding obligations tied to vesting restricted stock units, not at the CEO’s discretion. Following this tax-related sale, he directly holds 70,812 shares of Upstream Bio common stock.

Insights

CEO’s small share sale is a routine tax-related transaction.

The CEO of Upstream Bio, Inc., Everett Rand Sutherland, sold 2,095 shares of common stock at $6.10 per share. The filing explains this sale occurred under a company “sell-to-cover” policy for tax withholding on vesting restricted stock units.

Because the transaction was automatic and driven by tax obligations, it functions more like a mechanical payroll event than a discretionary stock sale. After the sale, Sutherland directly owns 70,812 shares, so the transaction represents a small portion of his reported holdings.

Insider Trade Summary

Net Seller: 2,095 shares

Net Sell 1 txn

Insider Sutherland Everett Rand

Role Chief Executive Officer

Sold 2,095 shs ($13K)

Type	Security	Shares	Price	Value
Sale	Common Stock	2,095	$6.10	$13K

Holdings After Transaction: Common Stock — 70,812 shares (Direct)

Footnotes (1)

F1. The Issuer has adopted a "sell-to-cover" policy to satisfy the tax withholding obligations of the Reporting Person. The sales reported on this Form 4 represent the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. Such sales were automatic and not at the discretion of the Reporting Person.

Key Figures

Shares sold: 2,095 shares Sale price: $6.10 per share Shares held after transaction: 70,812 shares

3 metrics

Shares sold 2,095 shares Open-market sale on 2026-06-16 to cover tax withholding

Sale price $6.10 per share Price for the 2,095 shares sold

Shares held after transaction 70,812 shares Direct holdings of CEO following the reported sale

Key Terms

sell-to-cover policy, tax withholding obligations, restricted stock units

3 terms

sell-to-cover policy financial

"The Issuer has adopted a "sell-to-cover" policy to satisfy the tax withholding obligations"

tax withholding obligations financial

"shares required to be sold by the Reporting Person to cover tax withholding obligations"

restricted stock units financial

"tax withholding obligations in connection with the vesting of restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/17/2026 - 04:05 PM Accepted by SEC EDGAR 06/17/2026 - 04:05 PM

FAQ

What insider transaction did Upstream Bio (UPB) report for its CEO?

Upstream Bio’s CEO, Everett Rand Sutherland, reported selling 2,095 shares of common stock. The shares were sold at $6.10 per share in a transaction linked to tax withholding on vesting restricted stock units.

Why did the Upstream Bio (UPB) CEO sell 2,095 shares of stock?

The CEO sold 2,095 shares to cover tax withholding obligations from vesting restricted stock units. The company has a sell-to-cover policy, so the sale was automatic and not at the reporting person’s discretion, according to the filing footnote.

At what price were the Upstream Bio (UPB) CEO’s shares sold?

The filing states that 2,095 shares of Upstream Bio common stock were sold at $6.10 per share. This price applies to the tax-related sell-to-cover transaction associated with the vesting of restricted stock units.

How many Upstream Bio (UPB) shares does the CEO hold after this Form 4?

After the reported transaction, CEO Everett Rand Sutherland directly holds 70,812 shares of Upstream Bio common stock. This shows the 2,095 shares sold for tax withholding represent a relatively small portion of his reported direct holdings.

Was the Upstream Bio (UPB) CEO’s stock sale discretionary?

No. The footnote explains the issuer adopted a sell-to-cover policy for tax withholding, and the reported sale represents the number of shares required to cover those obligations. The transaction was automatic and not at the CEO’s discretion.

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^*

Sutherland Everett Rand

(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
X	Officer (give title below)	Other (specify below)
	Chief Executive Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/16/2026		S⁽¹⁾		2,095	D	$6.1	70,812	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. The Issuer has adopted a "sell-to-cover" policy to satisfy the tax withholding obligations of the Reporting Person. The sales reported on this Form 4 represent the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. Such sales were automatic and not at the discretion of the Reporting Person.

	/s/ Allison Ambrose, Attorney-in-Fact	06/17/2026
	** 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)

Source: View Original Filing on SEC EDGAR