Thompson Peter A. 4

What Happened

• Peter A. Thompson, a director of Sionna Therapeutics, was recorded on Form 4 as receiving a grant/award (derivative) of 17,340 shares on 2026-06-17. The filing shows an acquisition price of $0.00 (i.e., no cash paid reported).

Key Details

• Transaction date: 2026-06-17; Form 4 filed: 2026-06-18 (timely filing).
• Amount: 17,340 shares; transaction type: Award/Grant (derivative); reported price: $0.00.
• Vesting: The award vests in full on the earlier of June 17, 2027 or the date of Sionna’s next annual meeting, subject to Thompson’s continued service (footnote F2).
• Transfer obligation: Thompson is obligated to transfer any securities or economic benefit from these awards to OrbiMed Advisors LLC and OrbiMed Capital GP VIII LLC, which will ensure they are provided to OrbiMed Private Investments VIII, LP (footnote F1) — indicating the economic beneficiary is an OrbiMed fund rather than Thompson personally.
• Shares owned after transaction: Not specified in the filing.

Context

• This was a grant/award (derivative instrument) rather than an open-market purchase or sale; the $0.00 report typically reflects an award/option grant rather than cash consideration. Because the filing indicates the securities will be transferred to an OrbiMed fund, this looks like an institutional allocation routed through the director, not a personal buy or sell.