June 16, 2026 · Form 4 insider transaction
Ambrose Allison sold 477 shares of Upstream Bio, Inc. at $6.10 per share, a transaction worth $2.9K. The trade was recorded as open-market sale and disclosed on an SEC Form 4, filed 1 day after the transaction.
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.