SUTRO BIOPHARMA, INC. 4

Heidi Hunter received an award of stock options for 10,000 shares of Sutro Biopharma, Inc. (STRO) common stock at a $26.09 exercise price.

On June 5, 2026, reporting person Heidi Hunter received a grant of stock options to purchase 10,000 shares of Sutro Biopharma, Inc. common stock at an exercise price of $26.09 per share, representing a compensatory equity award rather than an open-market transaction. The options will vest in monthly installments of 8.33% beginning July 5, 2026, and will be fully vested and exercisable by the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, with an expiration date of June 5, 2036. Following this award, Hunter holds 10,000 derivative securities (options) corresponding to 10,000 shares of common stock in a direct capacity, with an approximate notional value of about $260,900 based on the grant exercise price.

Filing Facts

CIK

1382101

Ticker

STRO

Form

4

Source Type

sec

Accession

0001891841-26-000002

Alert Tier

5