Reported relationships
Latest disclosed role at each company.
| Company | Last reported as | Report date | Published |
|---|---|---|---|
| Upstream Bio, Inc.UPB · Entity 5743 | General Counsel | September 16, 2026 | September 17, 2026 |
Disclosed balances
About these balances
Latest available filing per company, not a reconstructed current portfolio. Matching sequences show the last reported balance with all source rows expandable; grouping alone does not establish account ownership. Do not add unresolved positions together. Filings may omit unchanged positions, and amendments may correct only part of an older disclosure. Jointly reported shares are not necessarily this owner's personal holdings.
Upstream Bio, Inc.
Report date September 16, 2026 · Filed September 17, 2026
| Security / award | Ownership account | Disclosed shares / units | Disclosure context |
|---|---|---|---|
| Common StockSEC Table I · non-derivative | Direct | 15,563 |
Reported balance
After 2026-09-16 transaction · row 1
1 source rowRow 1 · 2026-09-16 · Sale · Disposed 485 · Balance 15,563 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. |
Filing footnotes · ownership attribution and instrument terms
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.
Transaction history
JSON APIPurchases/sales include open-market and private transactions. Plan disclosure applies to the filing; individual rows may differ. “Not disclosed” is not “unplanned.”
The cutoff filters transaction history only. Company summaries and owner relationships show the latest available disclosures. Parser corrections can improve historical records.
| Transaction date | Company | Activity / security | Shares / units | Reported price | Reported value | Details |
|---|---|---|---|---|---|---|
| September 16, 2026 Filed Sep 17, 2026 20:05 UTC | Upstream Bio, Inc. UPB · Entity 5743 | SaleCommon Stock | 485 | $5.49 | $2,662.65 |
DisclosureSEC source: 0001193125-26-394318 · ownership.xml · nonDerivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 15,563 F1 · kind: 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. Read SEC document |
| June 16, 2026 Filed Jun 17, 2026 20:05 UTC | Upstream Bio, Inc. UPB · Entity 5743 | SaleCommon Stock | 477 | $6.10 | $2,909.70 |
DisclosureSEC source: 0001193125-26-274119 · ownership.xml · nonDerivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 16,048 F1 · kind: 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. Read SEC document |
| March 16, 2026 Filed Mar 17, 2026 21:00 UTC | Upstream Bio, Inc. UPB · Entity 5743 | SaleCommon Stock | 475 | $9.29 | $4,412.75 |
DisclosureSEC source: 0001193125-26-111121 · ownership.xml · nonDerivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 16,525 F1 · kind: 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. Read SEC document |
| January 02, 2026 Filed Jan 6, 2026 22:15 UTC | Upstream Bio, Inc. UPB · Entity 5743 | GrantStock Option (Right to Buy) · Derivative | 51,000 | $0.00 Strike: $27.07 | $0.00 |
DisclosureSEC source: 0001193125-26-004756 · ownership.xml · derivative · entry 2 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 51,000 Underlying: Common Stock · 51,000 shares Expires 2036-01-01 F2 · derivative.exercise_date: 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. Read SEC document |
| January 02, 2026 Filed Jan 6, 2026 22:15 UTC | Upstream Bio, Inc. UPB · Entity 5743 | GrantCommon Stock | 17,000 | $0.00 | $0.00 |
DisclosureSEC source: 0001193125-26-004756 · ownership.xml · nonDerivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 17,000 F1 · kind: 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. Read SEC document |
| February 06, 2025 Filed Feb 7, 2025 22:25 UTC | Upstream Bio, Inc. UPB · Entity 5743 | GrantStock Option (Right to Buy) · Derivative | 25,000 | $0.00 Strike: $8.53 | $0.00 |
DisclosureSEC source: 0000950170-25-016460 · ownership.xml · derivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 25,000 Underlying: Common Stock · 25,000 shares Expires 2035-02-05 F1 · derivative.exercise_date: The shares underlying this option shall vest in forty-eight equal monthly installments following February 6, 2025, subject to the Reporting Person's continued service on each such vesting date. Read SEC document |
| December 16, 2024 Filed Dec 17, 2024 21:18 UTC | Upstream Bio, Inc. UPB · Entity 5743 | GrantStock Option (Right to Buy) · Derivative | 100,000 | $0.00 Strike: $19.01 | $0.00 |
DisclosureSEC source: 0000950170-24-137213 · ownership.xml · derivative · entry 1 Ambrose Allison · CIK 0002047381 · General Counsel 10b5-1 filing: No plan indicated Ownership: Direct Disclosed balance after: 100,000 Underlying: Common Stock · 100,000 shares Expires 2034-12-15 F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest on December 16, 2025, with the remainder vesting in thirty-six equal monthly installments thereafter, subject to the Reporting Person's continued service on such vesting date. Read SEC document |
Value uses the disclosed total when available, otherwise shares × reported transaction price. It is not an estimate of exercise cash cost or investment performance.