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Sionna Therapeutics, Inc.

SION
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0002036042

In the last 90 days, Sionna Therapeutics, Inc. insiders filed 0 open-market purchases and 4 sales; 146 institutions reported holding it in 13F filings for Q2 2026, worth $2.11B in total; Viking Global Investors is the only superinvestor holding it.

Open-market trades, last 90 days

Open-market purchases (P) and sales (S) by Sionna Therapeutics, Inc. insiders, counted by Form 4 filing. Trades with a flagged price and duplicate filings are left out.

Open-market buys
0 filings
Open-market sells
4 filings
3 insiders, $31.4M in total
Insiders trading
3
Net value
−$31.4M
Purchases minus sales

Insider roster

Directors, officers and 10% owners who have filed a Form 4 for Sionna Therapeutics, Inc., current and former, most recent filer first. Last reported holding is the position after the last non-derivative trade in their latest filing.

Insider roster for Sionna Therapeutics, Inc.
NameTitleLast reported holdingLast filingFilings, past year
RA Capital Healthcare Fund LPDirector3,448,812IndirectSep 21, 20265
Ra Capital Management, L.P.Director, 10% Owner3,448,812IndirectSep 21, 20265
Kolchinsky PeterDirector, 10% Owner3,448,812IndirectSep 21, 20265
Shah Rajeev M.Director, 10% Owner3,448,812IndirectSep 21, 20265
RA Capital Nexus Fund, L.P.Director3,448,812IndirectSep 21, 20265
RA Capital Nexus Fund III, L.P.Director3,448,812IndirectSep 21, 20265
Ridloff ElenaCFO and CBO133,069Sep 18, 20262
McKee CharlotteCMO and Head of R&D128,415Sep 18, 20262
Fitzpatrick JenniferCLO and Head of Program Mgmt.56,265Sep 18, 20265
Cloonan MichaelPresident & CEO765,393Sep 18, 20265
Thompson Peter A.Director2,469,959IndirectJul 9, 202611
OrbiMed Advisors LLCDirector2,469,959IndirectJul 9, 202610
OrbiMed Capital GP VIII LLCDirector2,469,959IndirectJul 9, 202610
Clancy Paul JDirector–Jun 18, 20261
Booth BruceDirector686,567IndirectJun 18, 20266
Stelzer LaurieDirector–Jun 18, 20261
Resnick JoshuaDirector–Jun 18, 20261
Viney Joanne L.Director–Jun 18, 20261
Fleming Harold EdwardDirector–Jun 18, 20261
Ruddy Marcella K.Director–Jun 18, 20261
Coulter James G10% Owner6,494,962IndirectJan 26, 20261
Winkelried Jon10% Owner6,494,962IndirectJan 26, 20261
TPG GP A, LLC10% Owner6,494,962IndirectJan 26, 20261
Beer Caroline StarkChief Business Officer–Jan 6, 20262
Atlas Venture Fund XI, L.P.10% Owner807,727IndirectFeb 10, 20250
Atlas Venture Associates XI, LLC10% Owner807,727IndirectFeb 10, 20250
Atlas Venture Associates XI, L.P.10% Owner807,727IndirectFeb 10, 20250
Atlas Venture Opportunity Fund II, L.P.10% Owner807,727IndirectFeb 10, 20250
Atlas Venture Associates Opportunity II, LLC10% Owner807,727IndirectFeb 10, 20250
Atlas Venture Associates Opportunity II, LP10% Owner807,727IndirectFeb 10, 20250

Insider trades

Each row adds up one type of transaction in one Form 4 filing. Only open-market purchases (P) and sales (S) are shown by default; use the filters to see grants, option exercises and other codes.

Insider trades
Filed (ET)Trade dateFiling delayInsiderTransactionSharesAvg priceValueHolding changeFlags
Sep 21, 2026 (view filing)6:56 PM ETSep 174 daysRA Capital Healthcare Fund LP and 5 othersDirectorSSale−3.45M$6.33−$21.8M−50.0%3.45M after2 lots
Jul 9, 2026 (view filing)4:47 PM ETJul 72 daysThompson Peter A.DirectorSSale−85.9K$44.86−$3.85M−3.4%2.47M after10b5-1Duplicate filing
Jul 9, 2026 (view filing)4:44 PM ETJul 72 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−85.9K$44.86−$3.85M−3.4%2.47M after10b5-1
Jul 7, 2026 (view filing)4:38 PM ETJul 61 dayFitzpatrick JenniferChief Legal OfficerSSale−10.3K$43.60−$446.9K−100.0%0 after10b5-1
Jul 2, 2026 (view filing)4:45 PM ETJun 302 daysThompson Peter A.DirectorSSale−115.8K$45.50−$5.27M−4.3%2.56M after10b5-1Duplicate filing
Jul 2, 2026 (view filing)4:42 PM ETJun 302 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−115.8K$45.50−$5.27M−4.3%2.56M after10b5-1
May 29, 2026 (view filing)8:57 PM ETMay 272 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−101$44.49−$4.49K0.0%2.67M after10b5-1Duplicate filing
May 29, 2026 (view filing)May 272 daysThompson Peter A.DirectorSSale−101$44.49−$4.49K0.0%2.67M after10b5-1
May 11, 2026 (view filing)6:58 PM ETMay 7-114 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−293.0K$45.62−$13.4M−9.9%2.67M after3 lots10b5-1Duplicate filing
May 11, 2026 (view filing)May 7-114 daysThompson Peter A.DirectorSSale−293.0K$45.62−$13.4M−9.9%2.67M after3 lots10b5-1
Apr 21, 2026 (view filing)8:40 PM ETApr 17-184 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−55.3K$44.67−$2.47M−1.8%2.96M after2 lots10b5-1Duplicate filing
Apr 21, 2026 (view filing)Apr 17-184 daysThompson Peter A.DirectorSSale−55.3K$44.67−$2.47M−1.8%2.96M after2 lots10b5-1
Apr 16, 2026 (view filing)7:03 PM ETApr 14-162 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−510.6K$44.94−$22.9M−14.5%3.02M after3 lots10b5-1Duplicate filing
Apr 16, 2026 (view filing)Apr 14-162 daysThompson Peter A.DirectorSSale−510.6K$44.94−$22.9M−14.5%3.02M after3 lots10b5-1
Mar 6, 2026 (view filing)Mar 51 dayFitzpatrick JenniferChief Legal OfficerSSale−10.3K$33.86−$347.1K−100.0%0 after10b5-1
Feb 4, 2026 (view filing)7:39 PM ETFeb 2-32 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−31.0K$44.58−$1.38M−0.9%3.53M after2 lots10b5-1Duplicate filing
Feb 4, 2026 (view filing)Feb 2-32 daysThompson Peter A.DirectorSSale−31.0K$44.58−$1.38M−0.9%3.53M after2 lots10b5-1
Jan 26, 2026 (view filing)5:24 PM ETJan 224 daysCoulter James G and 2 others10% OwnerSSale−250.0K$40.00−$10.0M−3.7%6.49M after
Dec 29, 2025 (view filing)8:44 PM ETDec 245 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−33.4K$44.55−$1.49M−0.9%3.56M after10b5-1Duplicate filing
Dec 29, 2025 (view filing)Dec 245 daysThompson Peter A.DirectorSSale−33.4K$44.55−$1.49M−0.9%3.56M after10b5-1
Dec 19, 2025 (view filing)7:29 PM ETDec 17-192 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−1.88K$44.49−$83.4K−0.1%3.60M after3 lots10b5-1Duplicate filing
Dec 19, 2025 (view filing)Dec 17-192 daysThompson Peter A.DirectorSSale−1.88K$44.49−$83.4K−0.1%3.60M after3 lots10b5-1
Dec 9, 2025 (view filing)Dec 54 daysFitzpatrick JenniferChief Legal OfficerSSale−10.3K$40.52−$415.3K−100.0%0 after10b5-1
Nov 26, 2025 (view filing)6:45 PM ETNov 24-262 daysOrbiMed Advisors LLC and 1 otherDirectorSSale−108.1K$44.55−$4.81M−2.9%3.60M after3 lots10b5-1Duplicate filing
Nov 26, 2025 (view filing)Nov 24-262 daysThompson Peter A.DirectorSSale−108.1K$44.55−$4.81M−2.9%3.60M after3 lots10b5-1
Nov 24, 2025 (view filing)5:43 PM ETNov 20-214 daysRA Capital Healthcare Fund LP and 5 othersDirector, 10% OwnerSSale−30.3K$39.61−$1.20M−16.0%159.0K after12 lots
Nov 19, 2025 (view filing)8:43 PM ETNov 17-192 daysRA Capital Healthcare Fund LP and 5 othersDirector, 10% OwnerSSale−136.4K$40.34−$5.50M−44.8%168.2K after24 lots
Oct 28, 2025 (view filing)9:05 PM ETOct 24-284 daysRA Capital Healthcare Fund LP and 5 othersDirector, 10% OwnerSSale−373.6K$39.51−$14.8M−64.1%209.4K after8 lots
Oct 22, 2025 (view filing)Oct 211 dayCloonan MichaelPresident & CEOSSale−99.8K$36.26−$3.62M−15.4%547.3K after4 lots10b5-1
Oct 21, 2025 (view filing)Oct 21Same dayBooth BruceDirectorSSale−88.9K$34.22−$3.04M−11.5%686.6K after10 lots10b5-1
Oct 20, 2025 (view filing)Oct 16-204 daysBooth BruceDirectorSSale−286.4K$32.30−$9.25M−29.0%702.0K after18 lots10b5-1
Oct 17, 2025 (view filing)Oct 15-162 daysCloonan MichaelPresident & CEOSSale−25.2K$31.27−$788.1K−4.4%547.3K after3 lots10b5-1
Oct 15, 2025 (view filing)Oct 10-155 daysBooth BruceDirectorSSale−194.9K$30.47−$5.94M−20.6%751.7K after12 lots10b5-1
Oct 7, 2025 (view filing)Oct 3-64 daysBooth BruceDirectorSSale−49.5K$29.99−$1.49M−5.9%785.5K after4 lots10b5-1
Oct 1, 2025 (view filing)Sep 29-Oct 12 daysBooth BruceDirectorSSale−78.7K$30.08−$2.37M−9.0%794.1K after6 lots10b5-1
Sep 30, 2025 (view filing)Sep 26-294 daysCloonan MichaelPresident & CEOSSale−25.0K$29.11−$727.9K−4.4%547.3K after2 lots10b5-1
Sep 5, 2025 (view filing)Sep 41 dayFitzpatrick JenniferChief Legal OfficerSSale−10.3K$23.12−$237.0K−100.0%0 after10b5-1
Sep 3, 2025 (view filing)Aug 29-Sep 25 daysRidloff ElenaCFO & Head of Corp. Dev.SSale−9.58K$25.09−$240.4K−19.9%38.5K after2 lots10b5-1
Aug 28, 2025 (view filing)Aug 26-272 daysCloonan MichaelPresident & CEOSSale−25.0K$24.97−$624.4K−4.4%547.3K after2 lots10b5-1
Aug 28, 2025 (view filing)Aug 26-282 daysRidloff ElenaCFO & Head of Corp. Dev.SSale−23.4K$25.70−$601.9K−32.7%48.1K after3 lots10b5-1
Aug 21, 2025 (view filing)Aug 201 dayCloonan MichaelPresident & CEOSSale−25.0K$22.75−$568.8K−4.4%547.3K after10b5-1
Aug 21, 2025 (view filing)Aug 19-202 daysRidloff ElenaCFO & Head of Corp. Dev.SSale−52.0K$21.62−$1.12M−42.1%71.5K after2 lots10b5-1
Jul 1, 2025 (view filing)5:03 PM ETJun 274 daysCoulter James G and 2 others10% OwnerPPurchase+60.0K$15.84+$950.4K+0.9%6.74M after
Feb 12, 2025 (view filing)5:21 PM ETFeb 102 daysCoulter James G and 2 others10% OwnerPPurchase+1.13M$18.00+$20.3M+20.2%6.68M after
Feb 10, 2025 (view filing)5:04 PM ETFeb 10Same dayRA Capital Healthcare Fund LP and 5 othersDirector, 10% OwnerPPurchase+1.13M$18.00+$20.3M+93.8%2.32M after2 lots
Feb 10, 2025 (view filing)4:28 PM ETFeb 10Same dayOrbiMed Advisors LLC and 1 otherDirectorPPurchase+550.0K$18.00+$9.90M+17.4%3.70M afterDuplicate filing
Feb 10, 2025 (view filing)4:05 PM ETFeb 10Same dayAtlas Venture Fund XI, L.P. and 5 others10% OwnerPPurchase+60.0K$18.00+$1.08M+8.0%807.7K afterDuplicate filing
Feb 10, 2025 (view filing)Feb 10Same dayThompson Peter A.DirectorPPurchase+550.0K$18.00+$9.90M+17.4%3.70M after
Feb 10, 2025 (view filing)Feb 10Same dayBooth BruceDirectorPPurchase+60.0K$18.00+$1.08M+8.0%807.7K after