Director William Ho of Spero Therapeutics, Inc. (NASDAQ:SPRO) filed a Form 4 on November 10, 2026, disclosing the acquisition of a stock option to purchase 100,000 shares of common stock at an exercise price of $1.01 per share.

Key Highlights

  • Reporting person: William Ho, identified as a Director of Spero Therapeutics, Inc.
  • Transaction date: November 10, 2026, with a transaction code of A (acquired).
  • Option grant: 100,000 stock options (right to buy) at an exercise price of $1.01 per share, acquired at a price of $0.00.
  • Expiration date: November 10, 2036.
  • Vesting schedule: Equal monthly installments until the third anniversary of the grant date, subject to continued service through each vesting date.
  • Post-transaction holdings: 100,000 derivative securities beneficially owned, held directly.

Stock Option Grant Details for Director William Ho at Spero Therapeutics

According to the Form 4 filed with the U.S. Securities and Exchange Commission, William Ho, a Director at Spero Therapeutics, Inc. (NASDAQ:SPRO), was granted a stock option to purchase 100,000 shares of the company's common stock. The transaction was dated November 10, 2026, and the option carries an exercise price of $1.01 per share. The filing indicates the option was acquired at a price of $0.00, consistent with a grant rather than a purchase.

The filing discloses that the option has an expiration date of November 10, 2036, giving it a ten-year term from the grant date. As described in the filing's explanation of responses, "the shares underlying this option shall vest in equal monthly installments until the third anniversary of the grant date, subject to the Reporting Person's continued service through the applicable vesting date." Following this transaction, Ho beneficially owns 100,000 derivative securities on a direct basis, according to the filing.

The Form 4 was signed by Maegan Deare, identified as Attorney-in-Fact for William Ho, and was filed on November 10, 2026. No non-derivative securities transactions were reported in Table I of the filing. The filing was made by one reporting person and does not indicate any amendment to a prior filing.

What Was Disclosed

Spero Therapeutics Director William Ho reported the acquisition of a stock option covering 100,000 shares of common stock at $1.01 per share, expiring November 10, 2036, with monthly vesting over three years subject to continued service, as disclosed in a Form 4 filed November 10, 2026.