Sionna Therapeutics, Inc. Common Stock (SION) Fair Value & Analysis

Healthcare · US · Market cap $250M

Below-average quality, and screening another 21% overvalued on our models.

What runs behind every stock

26 valuation models 8 families, DCF to NCAV 37 quality factors margins, balance sheet, cashflow, debt 6 AI factors moat, what no ratio measures 2,000+ data points verified, per stock, median

69 individual criteria per stock, every one traceable See the method →

What matters now

• Weak quality (32/100) and above fair value at the same time, the margin of safety is missing on both counts.
• A fairly wide model range ($2.76 to $5.23) leaves room in how you read the outcome.
• Evidence is limited here (fewer models, shorter history), so the fair value is a rougher estimate than usual.

Price vs Fair Value (18 months)

White line = price, green steps = our fair value per fiscal year, dashed = 300-day average. As of Aug 22, 2026.

How to read this chart

18‑month range $4.50 – $51.04 · fair‑value band $2.76 – $5.23 · the $5.29 price screens above the $4.18 fair value. Dashed = 300-day average. As of Aug 22, 2026.

Full chart & analysis →

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Analysis

Sionna Therapeutics, Inc. Common Stock (SION) currently trades at $5.29, while our model-based Fair Value estimate is $4.18, implying the stock looks roughly 21.0% overvalued today. The Quality Score stands at 32/100 (below-average quality), in the Healthcare sector. Bear case: priced above our estimate, the market already discounts strong expectations. Bull case: above-average quality can justify a premium, the entry price still matters most (evidence: low).

It earns a return on equity of -26.7%. The balance sheet holds a net cash position of $49.8M. Fundamentals as of Aug 22, 2026

Our scenario range runs from $2.76 (bear case) to $5.23 (bull case); at $5.29, the current price sits above that range. Bear and bull are the same models run on conservative and optimistic assumptions (margins, growth, valuation multiples), so a plausible valuation range, not a price target. For context, the median of 10 Healthcare peers we cover trades at -63% fair-value upside, at -21%, SION screens cheaper than that median.

Fair Value models

Each model estimates fair value its own way; the Fair Value above is the evidence-weighted blend. Evidence (0–100) measures how completely this model’s inputs are available: well-fed models carry more weight in the blend. The spread across models is intentional, each one stresses a different value driver; dividend models, for instance, come out structurally low when payout is small.

Key figures & financial health

Quality Score breakdown

About the company

Sionna Therapeutics, Inc., a clinical-stage biopharmaceutical company, researches and develops medicines for the treatment of cystic fibrosis (CF).

Full company description

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.

Company description, as reported by the company or data provider.

Revenue & earnings trend

FY2022 – FY2025 · reported fiscal years

Sionna Therapeutics, Inc. Common Stock reported revenue of $0 in FY2025 versus $0 in FY2022. Reported net income was −$75.3M in FY2025.

SION screens 21% overvalued. Compare with Vertex Pharmaceuticals Incorporated →

Earlier news

External third-party headlines (Yahoo Finance, Reuters and others), not an editorial selection.

• Tenax, Sionna plunge; MarineMax jumps premarket on reported buyout Yahoo Finance · Aug 10, 2026
• 5 Undervalued Stocks That Soared: SION +277%, FBRX +306%, NKTR +869% & More Nasdaq · Jul 19, 2026
• Wedbush Initiates Coverage of Sionna Therapeutics (SION) Yahoo Finance · May 14, 2026
• Sionna Insider Sells $2.5 Million in Stock Amid 215% Surge, but Here's What Investors Should Watch Yahoo Finance · Apr 27, 2026

Peer Group

Biotechnology · 627 stocks

How this stock ranks against its industry: the green marker is this stock, the band is the typical 25–75% peer range, and the tick is the median.

Valuation Multiples vs Biotechnology median · lower = cheaper

Snowflake

Five quick dimensions, each 0 to 100: VALUE (fair-value potential), FUTURE (revenue growth), PAST (return on equity), HEALTH (low debt), DIVIDEND (yield). Green = this stock, grey = typical sector peer.

Insider activity: 44/100

Values & ESG

Does this company touch areas you may want to avoid? The classification is inferred from sector and industry.

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Frequently asked questions

How we calculate Fair Value

Each company is valued through a stack of independent intrinsic-value models (DCF variants, residual-income, multiples and more), blended into one family-balanced consensus and weighted by how much trustworthy data backs it. A separate quality layer scores the fundamentals. Every input is real reported data, nothing guessed.