Sionna Therapeutics, Inc.
🔔 Watch stock
Assessment
Our Rating
A journalistic assessment by our editorial team at the time of the deep dive — it rates the company, not the entry point. Not investment advice and not a solicitation to buy or sell.
The business works in principle, but one material question is open. As long as it stays open, our findings do not carry a quality verdict.
Why this colour
The quality light is amber because this company's decisive operating question is open and, since August 10, 2026, more open than ever: whether the NBD1 thesis can be turned into proof of efficacy is unproven — the first test in patients showed no measurable effect, the tested indication has been dropped, and the remaining route sits in Phase 1. Red is not warranted, because the documented balance sheet risks are absent: the quarterly report for the period ended June 30, 2026 explicitly raises no going concern doubt, equity is positive at $265.8 million, there is no financial debt, and the cash runway sits far above the four-quarter threshold even at an unchanged burn rate. Green is not warranted either: no approved product, no revenue since the company was founded in August 2019, no demonstrated efficacy. This is a judgement about the company, not about the share price or entry timing — that is what the scanners decide, not this light. The decision is yours.
What the thesis turns on
Assessment: Opportunities & Risks
Sionna Therapeutics raised $579.2 million to test a single scientific thesis: that CFTR's NBD1 domain can be stabilized. On August 10, 2026 the first test in patients came back empty — the PreciSION CF Phase 2a trial missed its key endpoint with a placebo-adjusted change of -1.0 mmol/L at a p-value of 0.7, and SION-719 will not be advanced as an add-on to standard of care. What remains is an unusually clean balance sheet: $268.3 million of cash against $17.5 million of liabilities as of June 30, 2026, meaning about $250.8 million of net cash against a market capitalization of roughly $292 million (data as of August 14, 2026). Against that sit a Phase 1 program, a licensed lead compound carrying milestones of up to $440.0 million, and an unused $250.0 million dilution facility. Not investment advice.
Balance sheet and debt
As of June 30, 2026, $268.3 million of cash and securities faced only $17.5 million of total liabilities — no bank debt, no convertible notes, no sold royalty streams. Stockholders' equity is $265.8 million and net cash about $250.8 million, or $5.55 per share. For a company without revenue, that is an unusually clean starting position.
Proof of efficacy
The first test of the company thesis in patients produced no measurable effect: on August 10, 2026 the PreciSION CF Phase 2a trial reported a placebo-adjusted sweat chloride change of -1.0 mmol/L at a p-value of 0.7. SION-719 will not be advanced as an add-on to standard of care. One of the two planned routes to revenue is therefore closed.
Remaining program
The parallel Phase 1 trial in 120 healthy volunteers met its safety, tolerability and pharmacokinetic objectives, and SION-451 plus SION-2222 was named the preferred combination. The company says it is still evaluating next steps. A Phase 1 program at a company whose Phase 2a result has just failed to appear is an option, not a roadmap.
Capital structure and dilution
An "at the market" program for gross proceeds of up to $250.0 million has existed since March 2026 and was unused as of June 30, 2026 — roughly 86 percent of the market capitalization as of August 14, 2026. That it has not been drawn is a positive as of that date; after a share price decline of about 91 percent on August 10, 2026, using it would be particularly expensive for existing shareholders.
License dependency
The now-preferred combination partner SION-2222 comes from the July 2024 AbbVie agreement. It carries milestones of up to $360.0 million, up to a further $130.0 million through Galapagos, plus royalties and an AbbVie right of first negotiation ahead of a Phase 3 trial. Sanofi and the Cystic Fibrosis Foundation add up to $40.0 million each — together up to $440.0 million against $265.8 million of equity (June 30, 2026).
Cash runway
At $44.1 million of cash used in operations in the first half of 2026, the June 30, 2026 balance would cover a good three years at an unchanged pace (roughly $88 million a year). The quarterly report explicitly raises no doubt about the company's ability to continue as a going concern. The company's own "into 2028" statement, however, dates from August 6, 2026 and predates the trial result; no updated runway was available as of August 14, 2026.
Worth Noting
SION reached the research list through the Reddit run of our in-house stock scanner (as of August 14, 2026) — mentions jumped after the stock fell from $51.04 to $4.50 on August 10, 2026, on volume of 38.6 million shares against 747,500 the previous Friday.
Currency note: the most recent periodic report is the Form 10-Q for the quarter ended June 30, 2026 (filed August 6, 2026). Every filing from that date onward was reviewed; the decisive one is the Form 8-K dated August 10, 2026, which changes the picture. The "into 2028" cash runway dates from August 6, 2026 and is superseded by the later capital preservation announcement.
Name confusion: the company was founded in August 2019 as Sling Therapeutics, Inc. and has only been named Sionna Therapeutics, Inc. since November 2021. Older documents and the subsidiary still carry the former name.
Valuation figures are dated and evergreen: market capitalization roughly $292 million at $6.46 per share and 45,212,399 shares (price as of August 14, 2026, share count as of July 31, 2026); net cash roughly $250.8 million as of June 30, 2026; the IPO price was $18.00 on February 7, 2025. All as-of anchors, not forecasts.
Stock Watch
This analysis is as of August 26, 2026. Stock Watch will tell you what's changed at SION since then.
Later $1 a month per stock — signing up is free, and you'll be the first to know when it launches.
Price history
Chart
Interactive price chart (TradingView).
52-week range: 4.50 $ to 51.00 $ · Last price: 7.20 $ (As of: September 17, 2026)
Key figures
Key figures at a glance
Every figure we hold for this stock, grouped by topic. The question mark next to a label explains what the number means.
Basics
Performance
Technical Indicators
Calculated from the price history · as of 09/18/2026
Valuation
Profitability
Balance Sheet & Safety
Growth
Dividend
This stock currently pays no dividend.
Quality & Screener
Highlighted are things our editorial team noticed: green = stands out as strong, red = deserves a closer look. No single metric is a verdict on its own — always read it in context.
Comparison
Industry comparison
The stock alongside the largest companies in the same group. The median row is the middle value of the companies shown above — not of the whole industry.
Industry: Biotechnology
| Company | Market cap ($B) | P/E | EV/EBITDA | Gross Margin % | EBIT Margin % | Sales Growth (Year) % | Perf. 1Y % |
|---|---|---|---|---|---|---|---|
| Sionna Therapeutics, Inc. SION | 0.3 | – | 0.0 | – | 0.0 | – | -67.7 |
| Vertex Pharmaceuticals Inc VRTX | 130.6 | 31.3 | 24.5 | 55.0 | 38.1 | 9.6 | 33.4 |
| Regeneron Pharmaceuticals Inc REGN | 82.0 | 19.9 | 13.1 | 44.5 | 20.7 | 1.0 | 35.5 |
| Moderna Inc MRNA | 62.7 | – | 4.6 | -66.0 | -131.1 | -39.2 | 532.3 |
| argenx NV ARGX | 61.9 | 38.1 | 34.2 | 59.1 | 32.0 | 89.6 | 30.9 |
| Revolution Medicines Inc RVMD | 40.9 | – | -9.7 | -174,708.6 | 0.0 | -100.0 | 338.3 |
| BeiGene, Ltd. ONC | 40.0 | 63.1 | 34.1 | 88.9 | 19.1 | 40.2 | 6.4 |
| Alnylam Pharmaceuticals Inc ALNY | 32.6 | 61.8 | 28.4 | 79.7 | 23.0 | 65.2 | -48.1 |
| Royalty Pharma Plc RPRX | 32.5 | 31.8 | 19.6 | 95.8 | 100.3 | 5.1 | 68.6 |
| Median of companies shown | 40.9 | 34.9 | 19.6 | 57.0 | 20.7 | 7.3 | 33.4 |
Based on the most recently reported figures. Only stocks from the same trading venue are lined up, so the market caps are counted in one currency. Compare in a chart →
Fiscal years
Annual Figures
Fiscal years from the audited annual reports, oldest first. EBIT is the operating profit before interest and taxes; total assets are everything the company owns.
Revenue, operating income and net income per fiscal year $M
Revenue Operating income Net income
| Fiscal Year | Revenue ($M) | EBIT ($M) | Net Income ($M) | EPS ($) | Operating Cash Flow ($M) | Equity ($M) | Total Assets ($M) |
|---|---|---|---|---|---|---|---|
| 2022 | 0 | -41 | -40 | -0.91 | -36 | -70 | 87 |
| 2023 | 0 | -50 | -47 | -1.07 | -44 | -115 | 52 |
| 2024 | 0 | -71 | -62 | -1.40 | -53 | -164 | 186 |
| 2025 | 0 | -89 | -75 | -1.88 | -66 | 307 | 326 |
Quarters
Quarterly Figures
Each bar is one quarter, the last one is the most recent. Use the switch to step through the individual figures.
Revenue & Profit
Cash Flow
Balance Sheet
Margins
Per Share
Click the chart or tab into it, then use ← and → to step through the periods.
None of the selected stocks reports this metric. Pick another metric or switch between annual and quarterly.
· Total · per year
These companies report in different currencies — switch on “Indexed” or pick a margin for a fair comparison.
The figures could not be loaded right now.
Source: fundamental data
| Quarter | EPS (Earnings Per Share) | EPS YoY (%) | Sales ($M) | Sales YoY (%) | Net Margin (%) | OCF ($M) | FCF ($M) |
|---|---|---|---|---|---|---|---|
| 2024: Q4 | -3.38 | – | 0 | – | – | -12 | -12 |
| 2025: Q1 | -0.62 | – | 0 | – | – | -16 | -16 |
| 2025: Q2 | -0.41 | – | 0 | – | – | -18 | -18 |
| 2025: Q3 | -0.46 | – | 0 | – | – | -15 | -15 |
| 2025: Q4 | -0.46 | 86.40 | 0 | – | – | -17 | -17 |
| 2026: Q1 | -0.60 | 3.20 | 0 | – | – | -22 | -22 |
| 2026: Q2 | -0.66 | -61.00 | 0 | – | – | -44 | -44 |
What Do These Terms Mean?
- EPS (Earnings Per Share):
- Quarterly profit divided by the total share count — how much of the profit works out to a single share.
- YoY (Year over Year):
- Change versus the same quarter a year ago — this is how you compare without seasonal distortion (e.g. the holiday shopping season).
- Sales:
- All revenue for the quarter, before any costs are deducted — the top line of the income statement.
- Net Margin:
- What percentage of sales is left over as profit in the end. Negative means the company is posting a loss.
- OCF (Operating Cash Flow):
- The cash that actually flows into the till from the core business during the quarter — harder to dress up than book profit.
- FCF (Free Cash Flow):
- Operating cash flow minus capital expenditures — the money that's genuinely free to use, say for paying down debt, buybacks, or dividends.
Screening
Appears in These Scanners
This stock currently matches 11 of our scanner strategies — each hit links to the scanner.
Quality & Balance Sheet
Breakout & Setup
Momentum & Trend
Research
Only genuine hits from verified scanners count; pure ranking metrics (P/E, P/S, and similar, which just sort the whole universe) don't count as a hit. View all scanners
Outlook
Analysts & Price Target
Combined picture of the price targets and recommendations of every analyst covering the stock. Price targets are expectations for the next 12 months, not promises — and they often follow the price rather than predict it.
Distribution of Recommendations
Estimates by Fiscal Year
| Fiscal Year | EPS Estimate ($) | EPS Range ($) | Revenue Estimate ($M) | Expected Growth | Analysts |
|---|---|---|---|---|---|
| 12/31/2026 | -2.50 | -3.18 – -1.93 | 0 | -33.0% | 10 |
| 12/31/2027 | -2.52 | -4.62 – -1.24 | 0 | -0.7% | 10 |
Average of the analyst estimates for the coming fiscal years. The range shows how far the most optimistic and the most cautious estimate sit apart — the wider it is, the less certain the expectation.
Valuation
What is priced in?
Free cash flow over the past twelve months is negative, which rules out a serious reverse calculation. Any growth rate only makes a negative cash flow more negative; no present value comes out of it. What the price reflects here is therefore not a stream of cash flows, but the expectation that there will be one at all.
A simplified model calculation — not a forecast and not a recommendation.
AI classification
AI Rating
Sionna Therapeutics entwickelt niedermolekulare Wirkstoffe gegen Mukoviszidose; KI kommt in den SEC-Berichten ausschließlich als allgemeiner Risikofaktor in der Möglichkeitsform vor, weder als Produkt noch als beschriebener Bestandteil der Wirkstoffforschung.
View the full file — quotes, sources, reviewed filings
„We may use, and our vendors may incorporate, artificial intelligence, or AI, both in our own development and implementation of AI and through the adoption of commercially available tools."
Wir können künstliche Intelligenz (KI) einsetzen, und unsere Dienstleister können sie einbinden — sowohl bei unserer eigenen Entwicklung und Einführung von KI als auch durch die Nutzung handelsüblicher Werkzeuge.
10-K · 2026-03-02 · View SEC filing
„The use of AI presents risks and challenges that could adversely affect our business and reputation, including cybersecurity, data privacy, IT, confidentiality, regulatory, legal, operational, competitive, reputational, intellectual property and other risks."
Der Einsatz von KI bringt Risiken und Herausforderungen mit sich, die unser Geschäft und unseren Ruf beeinträchtigen können — darunter Risiken bei IT-Sicherheit, Datenschutz, IT, Vertraulichkeit, Regulierung, Recht, Betrieb, Wettbewerb, Reputation und geistigem Eigentum.
10-K · 2026-03-02 · View SEC filing
„For example, use of certain AI tools may increase the risk of unauthorized disclosure of confidential information, compromise of proprietary intellectual property, or inadvertent inclusion of third-party intellectual property or other protected material, which could result in disputes, claims of infringement, legal liabilities or financial losses."
So kann der Einsatz bestimmter KI-Werkzeuge das Risiko erhöhen, dass vertrauliche Informationen unbefugt offengelegt werden, eigenes geistiges Eigentum kompromittiert wird oder fremdes geistiges Eigentum beziehungsweise anderes geschütztes Material versehentlich einfließt — mit möglichen Streitigkeiten, Verletzungsvorwürfen, Haftung oder finanziellen Schäden als Folge.
10-Q · 2026-08-06 · View SEC filing
Filings Reviewed: 10-Q 2026-08-06 · 10-K 2026-03-02 · 8-K 2026-08-10 · 8-K 2026-08-06 · 10-Q 2026-05-12 · 10-K 2025-03-20
Rated on August 14, 2026 · How the Rating Is Built
Quality check
AAQS
1/10The AAQS (AlleAktien Quality Score) checks 10 quality criteria on growth, profitability, and balance-sheet strength — per the methodology developed and published by AlleAktien, calculated by us from our own fundamental data. A stock counts as a quality stock from 9 out of 10 points. Where a company has a shorter listing history, we calculate over the fiscal years available (at least five).
- Sales growth 10Y > 5% –
- Exp. sales growth 3Y > 5% –
- EBIT growth 10Y > 5% –
- Exp. EBIT growth 3Y > 5% –
- Net debt < 4x EBIT –
- EBIT positive, 10Y straight –
- Max. EBIT decline < 50% –
- Return on equity > 15% -24.5%
- ROCE > 15% -28.3%
- Expected return > 10% –
View stocks with the full AAQS score · Read the methodology at AlleAktien
Source: fundamental data
Insiders
Insider Transactions
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character.
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Jul 7, 2026 | Thompson Peter A. | Director | Sell | 85,918 | 44.86 | 3,854,281 |
| Jul 7, 2026 | Orbimed Advisors Llc | Director | Sell | 85,918 | 44.86 | 3,854,281 |
| Apr 18, 2026 | Orbimed Advisors Llc | Director | Sell | 2,948 | 44.52 | 131,245 |
| Apr 18, 2026 | Peter A Thompson | Director | Sell | 2,948 | 44.52 | 131,245 |
| Apr 17, 2026 | Orbimed Advisors Llc | Director | Sell | 52,397 | 44.68 | 2,341,098 |
| Apr 17, 2026 | Peter A Thompson | Director | Sell | 52,397 | 44.68 | 2,341,098 |
The company
About the Company
Sionna Therapeutics, Inc., a clinical-stage biopharmaceutical company, researches and develops medicines for the treatment of cystic fibrosis (CF). It develops galicaftor (SION-2222), a transmembrane domain 1 (TMD1)-directed cystic fibrosis transmembrane conductance regulator (CFTR) that has completed Phase 2 trial; navocaftor (SION-3067), a potentiator that has completed Phase 2 trial; SION-109, an intracellular loop 4 directed CFTR corrector that has completed Phase 1 trial; SION-2851, a TMD1-directed CFTR corrector that has completed Phase 1 trial; SION-451, which is nucleotide-binding domain 1 stabilizer in Phase 1 trial; and SION-719, which is nucleotide-binding domain 1 stabilizer in Phase 2a proof-of-concept trial. The company was formerly known as Sling Therapeutics, Inc. and changed its name to Sionna Therapeutics, Inc. in July 2021. Sionna Therapeutics, Inc. was incorporated in 2019 and is headquartered in Waltham, Massachusetts.
- Employees
- 59
- Headquarters
- Waltham, MA
- Address
- 21 Hickory Drive, 02451 Waltham, United States
- Phone
- 617 819 2020
- Website
- sionnatx.com
- IPO Date
- 02/07/2025
- ISIN
- US8294011080
Management
| Name | Title | Birth Year |
|---|---|---|
| Michael Cloonan M.B.A. | President, CEO & Director | 1972 |
| Elena H. Ridloff C.F.A. | Chief Financial Officer | 1980 |
| Caroline Stark Beer M.B.A. | Chief Business Officer | 1979 |
| Greg Hurlbut Ph.D. | Co-Founder & Senior VP of Discovery Research | – |
| Mark Munson Ph.D. | Co-founder & Senior VP of Medicinal Chemistry | – |
| Andy Chu | Vice President of Information & Technology | – |
| Jennifer Fitzpatrick J.D. | Chief Legal Officer | 1977 |
| Sarah J. Spencer | Vice President of Corporate Communications | – |
| Vanya Sagar | Chief People Officer | 1976 |
| Charlotte McKee M.D. | Chief Medical Officer | 1965 |
Executives per the latest required filings; titles kept in their original language. Source: fundamental data.
Filings
Company Filings (8-K)
An 8-K is the filing a US company must use to disclose material events immediately — takeovers, changes at the top, major contracts or payment troubles, for instance. The links open the original document at the US Securities and Exchange Commission (SEC).
- 09/14/2026 Sionna Therapeutics, Inc. (SION): Cost Associated with Exit or Disposal Activities; Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers; Other Events; Financial Statements and Exhibits SEC ↗
- 08/10/2026 Sionna Therapeutics, Inc. (SION): Other Events; Financial Statements and Exhibits SEC ↗
- 08/06/2026 Sionna Therapeutics, Inc. (SION): Results of Operations and Financial Condition; Financial Statements and Exhibits SEC ↗
Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.