Prothena Corporation (PRTA) Fair Value & Analysis
Healthcare · US · Market cap $468M
Prothena Corporation
PRTA · US
Fair value as of: Jul 24, 2026
From 1 valuation models · updated 17 days ago
Share price −11.1% over the past month.
Below-average quality, and screening another 41% overvalued on our models.
What matters now
- The price sits above even our optimistic bull case ($6.42). The favourable scenario is already priced in.
- Weak quality (37/100) and above fair value at the same time, the margin of safety is missing on both counts.
- The large gap to fair value rests on thin data (low evidence): fewer applicable models and a shorter history. Read it with extra caution.
- A fairly wide model range ($3.39 to $6.42) leaves room in how you read the outcome.
Price vs Fair Value (5 years)
White line = price, green steps = our fair value per fiscal year, dashed = 300-day average. As of Jul 24, 2026.
How to read this chart
60‑month range $4.58 – $78.89 · fair‑value band $3.39 – $6.42 · the $8.76 price screens above the $5.14 fair value. Dashed = 300-day average. As of Jul 24, 2026.
Analysis
Prothena Corporation (PRTA) currently trades at $8.76, while our model-based Fair Value estimate is $5.14, implying the stock looks roughly 41.3% overvalued today. The Quality Score stands at 37/100 (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).
Trailing-twelve-month revenue stands at $57.9M. It earns a return on equity of -40.3%. The balance sheet holds a net cash position of $294M. Fundamentals as of Jul 24, 2026
Our scenario range runs from $3.39 (bear case) to $6.42 (bull case); at $8.76, 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. The share trades about 26% below its 52-week high and 50% above its 52-week low, currently below its 200-day average. For context, the median of 10 Healthcare peers we cover trades at -43% fair-value upside, at -41%, PRTA 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.
All 1 models by family
Key figures & financial health
More key figures
Figures from reported company fundamentals · as of Jul 24, 2026. TTM = trailing twelve months.
Quality Score breakdown
Of which business quality 34 · Market factors (momentum, volatility) 54
Non-valuation factor families (profitability, growth, cashflow, financial strength, momentum …), each academically grounded. Valuation itself sits in the Fair Value and is deliberately excluded here to avoid double-counting.
About the company
Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation.
Full company description
Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation. Its product pipeline includes Prasinezumab, an investigational humanized monoclonal antibody which is in Phase 3 clinical trial for the treatment of parkinson's disease and other synucleinopathies. The company also develops Coramitug, an investigational antibody, which is in Phase 3 clinical trial for the treatment of transthyretin amyloidosis; BMS-986446, an anti-tau antibody which is in Phase 2 clinical trial to treat Alzheimer's disease; PRX019, an investigational antibody which is in Phase 1 clinical trial for the treatment of neurodegenerative diseases; and PRX123, a Dual Aß-Tau Vaccine, which is in preclinical trial for treating Alzheimer's disease. In addition, it develops discovery- and late-preclinical-stage programs include TDP-43 CYTOPE for the treatment of amyotrophic lateral sclerosis; PRX012, a next-generation anti-Aß antibody which is in phase 1 clinical trial to treat Alzheimer's disease; and PRX012-TfR, a preclinical program for the treatment of Alzheimer's disease. It has a license, development, and commercialization agreement with F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. to develop and commercialize antibodies that target a-synuclein, including prasinezumab; and master collaboration agreement with Bristol Myers Squibb to develop and commercialize antibodies targeting tau, TDP-43. Prothena Corporation plc was incorporated in 2012 and is based in Dublin, Ireland.
Company description, as reported by the company or data provider.
Revenue & earnings trend
FY2021 – FY2025 · reported fiscal years
Prothena Corporation reported revenue of $9.7M in FY2025 versus $201M in FY2021, a compound −53.1%/yr. Reported net income was −$244M in FY2025.
PRTA screens 41% overvalued. Compare with Vertex Pharmaceuticals Incorporated →
Peer Group
Biotechnology · 603 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.
VALUE 0: the price sits above our fair-value range.
Values & ESG
Does this company touch areas you may want to avoid? The classification is inferred from sector and industry.
ESG scores are not available for this stock yet. Values and ESG data are contextual and can differ between providers.
Similar stocks
10 more Biotechnology stocks, each showing price versus our Fair Value estimate (as of Jul 24, 2026).
| Stock | Price | Fair Value | vs Fair Value |
|---|---|---|---|
| Vertex Pharmaceuticals Incorporated VRTX | $486.03 | $278.78 | -43% |
| Regeneron Pharmaceuticals, Inc REGN | $664.45 | $594.40 | -11% |
| Samsung Biologics Co 207940 | 1,368,000 KRW | 1,091,384 KRW | -20% |
| Celltrion, Inc 068270 | 175,800 KRW | 76,325 KRW | -57% |
| WuXi Biologics (Cayman) Inc 2269 | HK$39.54 | HK$30.42 | -23% |
| Innovent Biologics, Inc 1801 | HK$86.70 | HK$19.66 | -77% |
| Sino Biopharmaceutical Limited 1177 | HK$5.26 | HK$3.36 | -36% |
| ALTEOGEN Inc 196170 | 276,500 KRW | 44,444 KRW | -84% |
| RemeGen Co 688331 | ¥134.02 | ¥26.99 | -80% |
| Biocon Limited BIOCON | ₹440.70 | ₹57.36 | -87% |
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Frequently asked questions
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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.
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