Deykin Aaron 4
4 · Upstream Bio, Inc. · Filed Jun 17, 2026
Research Summary
AI-generated summary of this filing
Upstream Bio (UPB) CMO Aaron Deykin Sells 895 Shares
What Happened
- Aaron Deykin, Chief Medical Officer of Upstream Bio (UPB), disposed of 895 shares on June 16, 2026. The shares were sold at $6.10 each for a total proceeds of $5,460. This transaction is reported as a sale (routine sell-to-cover) rather than a purchase or strategic disposition.
Key Details
- Transaction date and price: 2026-06-16 — sale of 895 shares at $6.10 per share (total $5,460).
- Transaction type/code: Sale (S). Footnote F1 indicates this was an automatic "sell-to-cover" to satisfy tax withholding connected to RSU vesting.
- Shares owned after transaction: Not specified in the provided summary; Form 4 notes (F2) that 1,405 shares were previously acquired under the 2024 Employee Stock Purchase Plan.
- Filing timeliness: Report filed 2026-06-17 for a 2026-06-16 transaction — appears timely.
- Footnotes: F1 = automatic sale to cover tax withholding for vested restricted stock units; F2 = includes 1,405 shares acquired under the 2024 ESPP.
Context
- Sell-to-cover transactions are routine administrative sales tied to tax withholding when restricted stock units vest and do not necessarily indicate a change in the insider’s view of the company. The small size ($5.5k) here suggests it was purely to meet withholding obligations.
Insider Transaction Report
Form 4
Deykin Aaron
Chief Medical Officer
Transactions
- Sale
Common Stock
[F1][F2]2026-06-16$6.10/sh−895$5,460→ 33,197 total
Footnotes (2)
- [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.
- [F2]Includes 1,405 shares of Common Stock previously acquired under the Issuer's 2024 Employee Stock Purchase Plan.
Signature
/s/ Allison Ambrose, Attorney-in-Fact|2026-06-17