Changes in Beneficial Ownership · 4
Upstream Bio, Inc.
UPBNASDAQEQUITYCurrent
Changes in Beneficial Ownership
Structured filing — 4
ownership.xml
Filing details
- Report period
- 2026-09-16
- Issuer
- Upstream Bio, Inc.
- Issuer CIK
- 0002022626
- Trading symbol
- UPB
Reporting owner 1
- Name
- GRAY MICHAEL
- Reporting owner CIK
- 0001271411
- Relationship
- Officer
- Officer title
- CFO and COO
- Address
- UPSTREAM BIO, INC., 890 WINTER STREET, SUITE 200, WALTHAM, MA, 02451
Non-derivative transactions
| Security | Transaction date | Code | Amount | A / D | Price (USD) | Owned after | Ownership |
|---|---|---|---|---|---|---|---|
| Common Stock | 2026-09-16 | S · Form 4[F1] | 853 | D | 5.49 | 27,942 | D |
Table key
- S · Form 4
- Sale on the market or privately
- D
- Direct
Footnotes
- 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.↩ 1
Signature 1
- Signed
- /s/ Allison Ambrose, Attorney-in-Fact
- Date
- 2026-09-17
Company context
Upstream Bio is a clinical-stage biotechnology company developing treatments for severe inflammatory respiratory diseases. The Company is developing verekitug, the only known antagonist currently in clinical development that targets and inhibits the receptor for thymic stromal lymphopoietin (TSLP), a cytokine which is a clinically validated driver of inflammatory response positioned upstream of multiple inflammatory pathways. With more than 500 participants treated with verekitug across its clinical development programs and positive Phase 2 results in chronic rhinosinusitis with nasal polyps (CRSwNP) and severe asthma, verekitug has a substantial body of clinical evidence supporting its advancement into Phase 3 development in both diseases. Verekitug is also being evaluated in an ongoing Phase 2 trial in chronic obstructive pulmonary disease (COPD). Upstream Bio is focused on leveraging verekitug’s differentiated mechanism, potency, and potential for extended dosing to develop a treatment that may deliver best-in-class efficacy and quarterly dosing for patients underserved by today’s standard of care. To learn more, please visit www.upstreambio.com.