Form 4: Upstream Bio CMO Sells Shares for Tax Obligations

Upstream Bio's Chief Medical Officer, Aaron Deykin, sold 894 shares of common stock to cover tax withholding obligations related to restricted stock unit vesting.

Summary

• Aaron Deykin, Chief Medical Officer of Upstream Bio, Inc. (UPB), reported a transaction involving the sale of common stock.
• The transaction occurred on March 16, 2026.
• A total of 894 shares of common stock were sold at a price of $9.29 per share.
• The sale was executed under the Issuer's "sell-to-cover" policy to satisfy tax withholding obligations associated with the vesting of restricted stock units.
• This sale was automatic and not at the discretion of Mr. Deykin.
• Following the transaction, Mr. Deykin beneficially owns 32,687 shares of common stock.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral event, as 'sell-to-cover' transactions are routine for tax purposes and do not reflect discretionary selling based on company performance or outlook.

Future Outlook

NA

Industry Context

StockSavvy.ai notes that 'sell-to-cover' transactions are a common practice for executives to meet tax obligations upon the vesting of equity awards, and typically do not signal a change in management's outlook on the company's prospects.

Stakeholder Impact

• Shareholders: The sale of 894 shares by a Chief Medical Officer is a minor transaction and is unlikely to have a significant impact on the overall shareholder base or stock price, as it is a routine tax-related event.

Key Dates

Recommendation

The reported transaction is a routine 'sell-to-cover' for tax obligations related to restricted stock unit vesting, not a discretionary sale based on the company's fundamentals. As such, it does not provide new information that would warrant a change in investment recommendation. Investors should hold their positions and monitor broader company performance and market trends.

Keywords

Upstream Bio, UPB, Aaron Deykin, Chief Medical Officer, Insider Trading, Form 4, Stock Sale, Restricted Stock Units, Tax Withholding, Sell-to-Cover