Spruce Street Capital LP, along with co-Managing Partners Alex R. Rosen and Simon Basseyn, filed a Schedule 13G with the SEC disclosing beneficial ownership of 393,700 shares of LeonaBio, Inc. common stock, representing 4.2% of the class, with a triggering event date of September 30, 2026.

Key Highlights

  • Three reporting persons: Spruce Street Capital LP (investment manager), Alex R. Rosen, and Simon Basseyn each reported beneficial ownership of 393,700 shares of LeonaBio common stock.
  • Ownership percentage: The 393,700 shares represent 4.2% of the outstanding class, calculated based on 9,421,663 shares outstanding as of August 12, 2026.
  • No sole voting or dispositive power: All 393,700 shares are held with shared voting power and shared dispositive power; sole voting and sole dispositive power are each reported as 0.
  • Warrants expired unexercised: As of September 30, 2026, the reporting persons were deemed to beneficially own 1,033,464 shares, including 639,763 shares issuable upon exercise of warrants; those warrants expired unexercised on October 18, 2026.
  • Prior ownership at 9.99%: As of September 30, 2026, the reporting persons were deemed to beneficially own 9.99% of outstanding shares, subject to a 9.99% blocker on the warrants.
  • Item 5 applicability: The filing was made under the ownership-of-5-percent-or-less-of-a-class provision, reflecting the post-warrant-expiration position of 4.2%.

Spruce Street Capital's Post-Warrant Position in LeonaBio

According to the filing, Spruce Street Capital LP serves as the investment manager to certain investment funds and accounts collectively referred to as the "Spruce Street Funds." The Schedule 13G names two additional reporting persons: Alex R. Rosen and Simon Basseyn, each identified as co-Managing Member of Spruce Street Capital GP LLC, the general partner of the investment manager, and co-Managing Partner of the investment manager. All three reporting persons list 777 Third Avenue, Suite 1704, New York, New York 10017 as their principal business address.

The filing discloses that as of September 30, 2026, the reporting persons may have been deemed to beneficially own 1,033,464 shares of common stock, which included 639,763 shares issuable upon the exercise of warrants. Those warrants were subject to a 9.99% blocker, meaning they were "not exercisable to the extent that following such exercise, taking into account all other shares of Common Stock beneficially owned by the Reporting Persons, the Reporting Persons would beneficially own in excess of 9.99% of the outstanding Common Stock," according to the filing. The warrants expired unexercised on October 18, 2026, reducing the reported beneficial ownership to 393,700 shares, or 4.2% of the class.

The percentage calculation is based on 9,421,663 shares of common stock outstanding as of August 12, 2026, as reported in LeonaBio's Quarterly Report on Form 10-Q for the period ended June 30, 2026, filed with the SEC on August 14, 2026. The filing further states that it "should not be construed as an admission that any of the foregoing persons or any Reporting Person is, for the purposes of Section 13 of the Act, the beneficial owner of the shares of Common Stock reported herein."

What Was Disclosed

Spruce Street Capital LP and two affiliated individuals filed a Schedule 13G disclosing a 4.2% beneficial ownership position in LeonaBio, Inc. common stock (393,700 shares), following the October 18, 2026 expiration of warrants that had previously brought their deemed ownership to 9.99%.