Booth Bruce sold SION

October 13, 2025 · Form 4 insider transaction

Booth Bruce sold 857 shares of Sionna Therapeutics, Inc. at $31.03 per share, a transaction worth $26.6K. The trade was recorded as open-market sale under a pre-scheduled Rule 10b5-1 plan and disclosed on an SEC Form 4, filed 2 days after the transaction.

Direction
Disposed (sell-side)
Shares
857
Price
$31.03
Total value
$26.6K
RoleDirector
SecurityCommon Stock
Transaction codeS: Open-market sale
Transaction dateOctober 13, 2025
Filing dateOctober 15, 2025
Shares owned after771,867
OwnershipIndirect
10b5-1 planYes
AmendedNo

Footnotes

This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by Atlas Venture Opportunity Fund II, L.P. on February 25, 2025.; These shares are held directly by Atlas Venture Opportunity Fund II, L.P. ("AVOF II"). The general partner of AVOF II is Atlas Venture Associates Opportunity II, L.P. ("AVAO II LP"). Atlas Venture Associates Opportunity II, LLC ("AVAO II LLC") is the general partner of AVAO II LP. The Reporting Person is a member of AVAO II LLC and disclaims beneficial ownership of such securities held by AVOF II, except to the extent of his pecuniary interest therein, if any.

View the original Form 4 on SEC EDGAR
Booth Bruce sold SION: October 13, 2025 | Insider Trading Screener