Sionna Therapeutics, Inc.
SION · Pharmaceutical Preparations · 45.2M shares · EDGAR filings ↗
Reference price $44.49 · est. market cap ~$2.0B — last insider sale, 2026-05-27 (estimated from the dated SEC Form 4 price × shares outstanding — not a live quote)
Grade
D46Clinical/early-stage biotech — cystic-fibrosis clinical, heavy burn ($67M), very cash-rich.
Strengths
- Liquidity — current ratio 20.6 (95th)
Risks
- Pre-revenue, deep losses — per metrics
- Pre-revenue/clinical-stage — history of losses & need for capital per risk factors
- Binary clinical & funding risk — per 10-K
Notable findings
- Cash burnNegative free cash flow (-66.7M)
- Fund exitedNotable fund(s) exited this quarter: VANGUARD GROUP INC
- Notable holderHeld by 4 notable fund(s): CITADEL ADVISORS LLC, STATE STREET CORP, GOLDMAN SACHS GROUP INC +1 more (as of 2026-03-31)
- Insider sellingInsider selling — 24 open-market sale(s) by 4 insider(s) (cluster of 4 insiders, ~$91M, last 6mo) Form 4 ↗
- Trial readout soonUpcoming trial readout ~2026-07 — PHASE2 · Cystic Fibrosis (CF)
Key metrics
Return on equity
-24.5%
Return on assets
-23.1%
Current ratio
20.6×
Free cash flow
-$67M
Tangible book value
$307M
Cash & investments
$58M
Cash runway
4q
Insider transactions · last 18 months
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| 2026-05-27 | Thompson Peter A. | Sell | 101 | $44.49 |
| 2026-05-27 | ORBIMED ADVISORS LLC | Sell | 101 | $44.49 |
| 2026-05-11 | Thompson Peter A. | Sell | 185K | $46.22 |
| 2026-05-11 | ORBIMED ADVISORS LLC | Sell | 185K | $46.22 |
| 2026-05-08 | ORBIMED ADVISORS LLC | Sell | 60K | $44.58 |
| 2026-05-08 | Thompson Peter A. | Sell | 60K | $44.58 |
| 2026-05-07 | ORBIMED ADVISORS LLC | Sell | 49K | $44.61 |
| 2026-05-07 | Thompson Peter A. | Sell | 49K | $44.61 |
| 2026-04-18 | Thompson Peter A. | Sell | 2.9K | $44.52 |
| 2026-04-18 | ORBIMED ADVISORS LLC | Sell | 2.9K | $44.52 |
| 2026-04-17 | Thompson Peter A. | Sell | 52K | $44.68 |
| 2026-04-17 | ORBIMED ADVISORS LLC | Sell | 52K | $44.68 |
| 2026-04-16 | ORBIMED ADVISORS LLC | Sell | 227K | $45.34 |
| 2026-04-16 | Thompson Peter A. | Sell | 227K | $45.34 |
| 2026-04-15 | Thompson Peter A. | Sell | 236K | $44.64 |
| 2026-04-15 | ORBIMED ADVISORS LLC | Sell | 236K | $44.64 |
| 2026-04-14 | Thompson Peter A. | Sell | 48K | $44.51 |
| 2026-04-14 | ORBIMED ADVISORS LLC | Sell | 48K | $44.51 |
| 2026-03-05 | Fitzpatrick Jennifer | Option exercise | 10K | $6.11 |
| 2026-03-05 | Fitzpatrick Jennifer | Sell | 10K | $33.86 |
| 2026-02-03 | Thompson Peter A. | Sell | 29K | $44.58 |
| 2026-02-03 | ORBIMED ADVISORS LLC | Sell | 29K | $44.58 |
| 2026-02-02 | Thompson Peter A. | Sell | 1.9K | $44.57 |
| 2026-02-02 | ORBIMED ADVISORS LLC | Sell | 1.9K | $44.57 |
| 2026-01-22 | TPG GP A, LLC | Sell | 250K | $40.00 |
| 2025-12-24 | Thompson Peter A. | Sell | 33K | $44.55 |
| 2025-12-24 | ORBIMED ADVISORS LLC | Sell | 33K | $44.55 |
| 2025-12-19 | Thompson Peter A. | Sell | 875 | $44.49 |
| 2025-12-19 | ORBIMED ADVISORS LLC | Sell | 875 | $44.49 |
| 2025-12-18 | ORBIMED ADVISORS LLC | Sell | 100 | $44.49 |
| 2025-12-18 | Thompson Peter A. | Sell | 100 | $44.49 |
| 2025-12-17 | ORBIMED ADVISORS LLC | Sell | 900 | $44.50 |
| 2025-12-17 | Thompson Peter A. | Sell | 900 | $44.50 |
| 2025-12-05 | Fitzpatrick Jennifer | Option exercise | 10K | $6.11 |
| 2025-12-05 | Fitzpatrick Jennifer | Sell | 10K | $40.52 |
| 2025-11-26 | Thompson Peter A. | Sell | 1.6K | $44.49 |
| 2025-11-26 | ORBIMED ADVISORS LLC | Sell | 1.6K | $44.49 |
| 2025-11-25 | Thompson Peter A. | Sell | 12K | $44.60 |
| 2025-11-25 | ORBIMED ADVISORS LLC | Sell | 12K | $44.60 |
| 2025-11-24 | ORBIMED ADVISORS LLC | Sell | 95K | $44.54 |
| 2025-11-24 | Thompson Peter A. | Sell | 95K | $44.54 |
| 2025-11-21 | RA CAPITAL MANAGEMENT, L.P. | Sell | 6.4K | $39.50 |
| 2025-11-21 | RA CAPITAL MANAGEMENT, L.P. | Sell | 7.6K | $39.50 |
| 2025-11-21 | RA CAPITAL MANAGEMENT, L.P. | Sell | 1.2K | $39.50 |
| 2025-11-21 | RA CAPITAL MANAGEMENT, L.P. | Sell | 9.9K | $39.50 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 801 | $39.89 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 947 | $39.89 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 96 | $40.50 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 788 | $40.50 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 512 | $40.50 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 604 | $40.50 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 150 | $39.89 |
| 2025-11-20 | RA CAPITAL MANAGEMENT, L.P. | Sell | 1.2K | $39.89 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 19K | $40.01 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 2.3K | $40.01 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 12K | $40.01 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 14K | $40.01 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 2 | $40.61 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 12 | $40.61 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 8 | $40.61 |
| 2025-11-19 | RA CAPITAL MANAGEMENT, L.P. | Sell | 9 | $40.61 |
| 2025-11-18 | RA CAPITAL MANAGEMENT, L.P. | Sell | 332 | $39.57 |
| 2025-11-18 | RA CAPITAL MANAGEMENT, L.P. | Sell | 2.7K | $39.57 |
| 2025-11-18 | RA CAPITAL MANAGEMENT, L.P. | Sell | 1.8K | $39.57 |
| 2025-11-18 | RA CAPITAL MANAGEMENT, L.P. | Sell | 2.1K | $39.57 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 280 | $42.10 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 331 | $42.10 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 9.1K | $41.05 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 11K | $41.05 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 53 | $42.10 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 433 | $42.10 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 2.2K | $40.20 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 18K | $40.20 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 12K | $40.20 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 14K | $40.20 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 1.7K | $41.05 |
| 2025-11-17 | RA CAPITAL MANAGEMENT, L.P. | Sell | 14K | $41.05 |
| 2025-10-28 | RA CAPITAL MANAGEMENT, L.P. | Sell | 3.6K | $39.58 |
| 2025-10-28 | RA CAPITAL MANAGEMENT, L.P. | Sell | 17K | $39.58 |
| 2025-10-28 | RA CAPITAL MANAGEMENT, L.P. | Sell | 10K | $39.58 |
| 2025-10-28 | RA CAPITAL MANAGEMENT, L.P. | Sell | 31K | $39.58 |
| 2025-10-24 | RA CAPITAL MANAGEMENT, L.P. | Sell | 14K | $39.50 |
| 2025-10-24 | RA CAPITAL MANAGEMENT, L.P. | Sell | 122K | $39.50 |
| 2025-10-24 | RA CAPITAL MANAGEMENT, L.P. | Sell | 67K | $39.50 |
| 2025-10-24 | RA CAPITAL MANAGEMENT, L.P. | Sell | 108K | $39.50 |
| 2025-10-21 | Cloonan Michael | Option exercise | 34K | $6.11 |
| 2025-10-21 | Cloonan Michael | Option exercise | 13K | $6.11 |
| 2025-10-21 | Cloonan Michael | Sell | 13K | $34.44 |
| 2025-10-21 | Cloonan Michael | Option exercise | 30K | $6.11 |
| 2025-10-21 | Cloonan Michael | Sell | 30K | $35.63 |
| 2025-10-21 | Cloonan Michael | Option exercise | 23K | $6.11 |
| 2025-10-21 | Cloonan Michael | Sell | 23K | $36.60 |
| 2025-10-21 | Cloonan Michael | Sell | 34K | $37.31 |
| 2025-10-21 | Booth Bruce | Sell | 22K | $32.69 |
| 2025-10-21 | Booth Bruce | Sell | 4.7K | $32.69 |
| 2025-10-21 | Booth Bruce | Sell | 20K | $33.87 |
| 2025-10-21 | Booth Bruce | Sell | 4.2K | $33.87 |
| 2025-10-21 | Booth Bruce | Sell | 5.8K | $34.91 |
| 2025-10-21 | Booth Bruce | Sell | 1.2K | $34.91 |
| 2025-10-21 | Booth Bruce | Sell | 25K | $35.69 |
| 2025-10-21 | Booth Bruce | Sell | 5.3K | $35.69 |
| 2025-10-21 | Booth Bruce | Sell | 83 | $36.42 |
| 2025-10-21 | Booth Bruce | Sell | 17 | $36.42 |
| 2025-10-20 | Booth Bruce | Sell | 20K | $31.79 |
| 2025-10-20 | Booth Bruce | Sell | 4.3K | $31.79 |
| 2025-10-20 | Booth Bruce | Sell | 5.4K | $32.33 |
| 2025-10-20 | Booth Bruce | Sell | 26K | $32.33 |
| 2025-10-17 | Booth Bruce | Sell | 248 | $33.47 |
| 2025-10-17 | Booth Bruce | Sell | 29K | $32.10 |
| 2025-10-17 | Booth Bruce | Sell | 52 | $33.47 |
| 2025-10-17 | Booth Bruce | Sell | 6.0K | $32.10 |
| 2025-10-17 | Booth Bruce | Sell | 21K | $32.71 |
| 2025-10-17 | Booth Bruce | Sell | 4.5K | $32.71 |
| 2025-10-16 | Booth Bruce | Sell | 9.5K | $31.69 |
| 2025-10-16 | Booth Bruce | Sell | 8.6K | $30.15 |
| 2025-10-16 | Booth Bruce | Sell | 1.8K | $30.15 |
| 2025-10-16 | Booth Bruce | Sell | 45K | $31.69 |
| 2025-10-16 | Booth Bruce | Sell | 73K | $32.84 |
| 2025-10-16 | Booth Bruce | Sell | 15K | $32.84 |
| 2025-10-16 | Booth Bruce | Sell | 13K | $33.38 |
| 2025-10-16 | Booth Bruce | Sell | 2.7K | $33.38 |
| 2025-10-16 | Cloonan Michael | Option exercise | 10K | $6.11 |
| 2025-10-16 | Cloonan Michael | Sell | 10K | $31.46 |
| 2025-10-16 | Cloonan Michael | Option exercise | 200 | $6.11 |
| 2025-10-16 | Cloonan Michael | Sell | 200 | $34.00 |
| 2025-10-15 | Booth Bruce | Sell | 66K | $30.37 |
| 2025-10-15 | Cloonan Michael | Sell | 15K | $31.11 |
| 2025-10-15 | Cloonan Michael | Option exercise | 15K | $6.11 |
| 2025-10-15 | Booth Bruce | Sell | 6.3K | $31.12 |
| 2025-10-15 | Booth Bruce | Sell | 30K | $31.12 |
| 2025-10-15 | Booth Bruce | Sell | 14K | $30.37 |
| 2025-10-14 | Booth Bruce | Sell | 105 | $29.95 |
| 2025-10-14 | Booth Bruce | Sell | 501 | $29.95 |
| 2025-10-13 | Booth Bruce | Sell | 4.1K | $31.03 |
| 2025-10-13 | Booth Bruce | Sell | 857 | $31.03 |
| 2025-10-13 | Booth Bruce | Sell | 44K | $30.32 |
| 2025-10-13 | Booth Bruce | Sell | 9.2K | $30.32 |
| 2025-10-10 | Booth Bruce | Sell | 3.5K | $29.98 |
| 2025-10-10 | Booth Bruce | Sell | 17K | $29.98 |
| 2025-10-06 | Booth Bruce | Sell | 2.0K | $29.95 |
| 2025-10-06 | Booth Bruce | Sell | 9.8K | $29.95 |
| 2025-10-03 | Booth Bruce | Sell | 6.5K | $30.00 |
| 2025-10-03 | Booth Bruce | Sell | 31K | $30.00 |
| 2025-10-01 | Booth Bruce | Sell | 165 | $29.95 |
| 2025-10-01 | Booth Bruce | Sell | 35 | $29.95 |
| 2025-09-30 | Booth Bruce | Sell | 10K | $30.06 |
| 2025-09-30 | Booth Bruce | Sell | 2.1K | $30.06 |
| 2025-09-29 | Booth Bruce | Sell | 55K | $30.09 |
| 2025-09-29 | Booth Bruce | Sell | 11K | $30.09 |
| 2025-09-29 | Cloonan Michael | Option exercise | 7.8K | $6.11 |
| 2025-09-29 | Cloonan Michael | Sell | 7.8K | $29.70 |
| 2025-09-26 | Cloonan Michael | Sell | 17K | $28.85 |
| 2025-09-26 | Cloonan Michael | Option exercise | 17K | $6.11 |
| 2025-09-04 | Fitzpatrick Jennifer | Option exercise | 10K | $6.11 |
| 2025-09-04 | Fitzpatrick Jennifer | Sell | 10K | $23.12 |
| 2025-09-02 | Ridloff Elena | Sell | 8.8K | $25.08 |
| 2025-08-29 | Ridloff Elena | Sell | 748 | $25.18 |
| 2025-08-28 | Ridloff Elena | Sell | 16K | $25.97 |
| 2025-08-27 | Ridloff Elena | Sell | 3.6K | $25.10 |
| 2025-08-27 | Cloonan Michael | Option exercise | 7.4K | $6.11 |
| 2025-08-27 | Cloonan Michael | Sell | 7.4K | $25.01 |
| 2025-08-26 | Ridloff Elena | Sell | 3.7K | $25.13 |
| 2025-08-26 | Cloonan Michael | Option exercise | 18K | $6.11 |
| 2025-08-26 | Cloonan Michael | Sell | 18K | $24.96 |
| 2025-08-20 | Ridloff Elena | Sell | 18K | $22.69 |
| 2025-08-20 | Cloonan Michael | Option exercise | 25K | $6.11 |
| 2025-08-20 | Cloonan Michael | Sell | 25K | $22.75 |
| 2025-08-19 | Ridloff Elena | Sell | 34K | $21.08 |
| 2025-06-27 | TPG GP A, LLC | Buy | 60K | $15.84 |
| 2025-02-10 | Thompson Peter A. | Buy | 550K | $18.00 |
| 2025-02-10 | TPG GP A, LLC | Conversion | 4.9M | — |
| 2025-02-10 | TPG GP A, LLC | Buy | 1.1M | $18.00 |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Conversion | 5.0M | — |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Conversion | 527K | — |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Conversion | 2.2M | — |
| 2025-02-10 | Thompson Peter A. | Conversion | 3.2M | — |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Conversion | 180K | — |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Buy | 1.0M | $18.00 |
| 2025-02-10 | RA CAPITAL MANAGEMENT, L.P. | Buy | 102K | $18.00 |
| 2025-02-10 | Atlas Venture Fund XI, L.P. | Conversion | 2.9M | — |
| 2025-02-10 | Atlas Venture Fund XI, L.P. | Conversion | 748K | — |
| 2025-02-10 | Atlas Venture Fund XI, L.P. | Buy | 60K | $18.00 |
| 2025-02-10 | Booth Bruce | Conversion | 2.9M | — |
| 2025-02-10 | Booth Bruce | Buy | 60K | $18.00 |
| 2025-02-10 | ORBIMED ADVISORS LLC | Buy | 550K | $18.00 |
| 2025-02-10 | ORBIMED ADVISORS LLC | Conversion | 3.2M | — |
| 2025-02-10 | Booth Bruce | Conversion | 748K | — |
All non-derivative Form 4 activity (SEC), newest first.
Clinical trials
| Trial | Title | Phase | Status | Primary completion |
|---|---|---|---|---|
| NCT07108153 ↗ | Proof-of-concept Study to Evaluate the Safety, Tolerability, Pharmacodynamics, and Pharmacokinetics of SION-719 When Added to Trikafta Cystic Fibrosis (CF) | PHASE2 | Active Not Recruiting | 2026-07-01 |
| NCT07035990 ↗ | Safety, Tolerability, and Pharmacokinetics of Multiple Dose Combinations of SION-451 and Complementary Modulators SION-2222 and SION-109 in Healthy Participants. Cystic Fibrosis (CF) | PHASE1 | Recruiting | 2026-06-01 |
Source: ClinicalTrials.gov (U.S. NIH) · active studies first.
Notable events (8-K)
Recent filings
| Form | Filed | Period | Accession |
|---|---|---|---|
| 8-K | 2026-06-18 | 2026-06-17 | 0001628280-26-044263 ↗ |
| 10-Q | 2026-05-12 | 2026-03-31 | 0001628280-26-033876 ↗ |
| 8-K | 2026-05-12 | 2026-05-12 | 0001628280-26-033870 ↗ |
| 10-K | 2026-03-02 | 2025-12-31 | 0001628280-26-012996 ↗ |
| 8-K | 2026-03-02 | 2026-03-02 | 0001628280-26-012993 ↗ |
| 10-Q | 2025-11-05 | 2025-09-30 | 0001628280-25-049251 ↗ |
| 8-K | 2025-11-05 | 2025-11-05 | 0001628280-25-049246 ↗ |
| 8-K | 2025-08-11 | 2025-08-11 | 0002036042-25-000044 ↗ |
| 10-Q | 2025-08-11 | 2025-06-30 | 0002036042-25-000047 ↗ |
| 8-K | 2025-06-13 | 2025-06-12 | 0002036042-25-000018 ↗ |
| 8-K | 2025-06-04 | 2025-06-04 | 0001193125-25-134462 ↗ |
| 10-Q | 2025-05-12 | 2025-03-31 | 0002036042-25-000016 ↗ |