(PRTA) Prothena - Overview

Sector: Healthcare | Industry: Biotechnology | Exchange: NASDAQ (USA) | Market Cap: 490m USD | Total Return: 114.6% in 12m

Monoclonal Antibodies, Immunotherapies, Vaccines, Neurological Treatments
Total Rating 39
Safety 51
Buy Signal -0.19
Biotechnology
Industry Rotation: -9.6
Market Cap: 490M
Avg Turnover: 5.04M
Risk 3d forecast
Volatility60.6%
VaR 5th Pctl9.95%
VaR vs Median-0.44%
Reward TTM
Sharpe Ratio0.94
Rel. Str. IBD78.1
Rel. Str. Peer Group50.2
Character TTM
Beta1.507
Beta Downside2.215
Hurst Exponent0.479
Drawdowns 3y
Max DD94.01%
CAGR/Max DD-0.50
CAGR/Mean DD-0.67
EPS (Earnings per Share) EPS (Earnings per Share) of PRTA over the last years for every Quarter: "2021-03": -0.91, "2021-06": 0.58, "2021-09": 2.13, "2021-12": -0.71, "2022-03": -0.78, "2022-06": -0.88, "2022-09": -0.97, "2022-12": 0.12, "2023-03": -0.89, "2023-06": -1.03, "2023-09": 0.38, "2023-12": -1.26, "2024-03": -1.34, "2024-06": 1.22, "2024-09": -1.1, "2024-12": -1.08, "2025-03": -1.12, "2025-06": -1.73, "2025-09": -0.67, "2025-12": -0.4569, "2026-03": 0.6832,
Last SUE: 1.24
Qual. Beats: 1
Revenue Revenue of PRTA over the last years for every Quarter: 2021-03: 0.16, 2021-06: 60.071, 2021-09: 139.174, 2021-12: 1.172, 2022-03: 1.153, 2022-06: 1.312, 2022-09: 1.517, 2022-12: 49.923, 2023-03: 2.169, 2023-06: 4.019, 2023-09: 84.866, 2023-12: 0.316, 2024-03: 0.05, 2024-06: 132.014, 2024-09: 0.97, 2024-12: 2.123, 2025-03: 2.828, 2025-06: 4.42, 2025-09: 2.415, 2025-12: 0.021, 2026-03: 51.084,
Rev. CAGR: -50.66%
Rev. Trend: -56.9%
Last SUE: 1.16
Qual. Beats: 1

Warnings

High Debt while negative Cash Flow

Interest Coverage Ratio -3.8 is critical

Altman Z'' -15.00 < 1.0 - financial distress zone

Volatile

Tailwinds

No distinct edge detected

Description: PRTA Prothena

Prothena Corporation plc (PRTA) is a Dublin-based biotechnology firm specialized in protein dysregulation therapies. The company manages a clinical-stage pipeline targeting neurodegenerative and amyloid diseases, including Alzheimer’s, Parkinson’s, and transthyretin amyloidosis. Its lead assets, Prasinezumab and Coramitug, are currently in Phase 3 clinical trials.

The company utilizes a partnership-heavy business model, maintaining strategic development agreements with industry leaders F. Hoffmann-La Roche and Bristol Myers Squibb. In the biotechnology sector, such collaborations are standard for late-stage clinical companies to mitigate the high capital expenditures and regulatory risks associated with bringing novel biologics to market.

To better understand how these clinical milestones impact valuation, you may wish to review the deeper metrics available on ValueRay. Prothena’s focus on monoclonal antibodies and vaccines for protein misfolding positions it within a specialized niche of the biopharmaceutical industry aimed at high-prevalence, high-unmet-need neurological conditions.

Headlines to Watch Out For
  • Phase 3 clinical trial results for prasinezumab drive Parkinsons disease treatment valuation
  • Clinical data readouts for coramitug determine competitiveness in transthyretin amyloidosis market
  • Milestone payments from Roche and Bristol Myers Squibb impact cash runway
  • Regulatory approval timelines for Alzheimers pipeline influence long-term revenue projections
  • R&D expenditure levels for early-stage neurodegenerative programs affect quarterly earnings volatility
Piotroski VR-10 (Strict) 1.0
Net Income: -151.2m TTM > 0 and > 6% of Revenue
FCF/TA: -0.23 > 0.02 and ΔFCF/TA 3.09 > 1.0
NWC/Revenue: 529.3% < 20% (prev 281.1%; Δ 248.2% < -1%)
CFO/TA -0.23 > 3% & CFO -81.3m > Net Income -151.2m
Net Debt/EBITDA: error (EBITDA <= 0)
Current Ratio: 10.43 > 1.5 & < 3
Outstanding Shares: last quarter (54.1m) vs 12m ago 0.52% < -2%
Gross Margin: 93.61% > 18% (prev 0.58%; Δ 9.30k% > 0.5%)
Asset Turnover: 13.71% > 50% (prev 27.85%; Δ -14.14% > 0%)
Interest Coverage Ratio: -3.81 > 6 (EBITDA TTM -81.7m / Interest Expense TTM 22.0m)
Altman Z'' -15.00
A: 0.88 (Total Current Assets 339.2m - Total Current Liabilities 32.5m) / Total Assets 349.9m
B: -3.75 (Retained Earnings -1.31b / Total Assets 349.9m)
C: -0.20 (EBIT TTM -84.0m / Avg Total Assets 422.6m)
D: -35.23 (Book Value of Equity -1.31b / Total Liabilities 37.3m)
Altman-Z'' = -44.81 = D
What is the price of PRTA shares?

As of May 25, 2026, the stock is trading at USD 9.83 with a total of 510,853 shares traded.
Over the past week, the price has changed by +0.72%, over one month by -8.56%, over three months by +9.59% and over the past year by +114.63%.

Is PRTA a buy, sell or hold?

Prothena has received a consensus analysts rating of 3.50. Therefore, it is recommended to hold PRTA.

  • StrongBuy: 1
  • Buy: 2
  • Hold: 2
  • Sell: 1
  • StrongSell: 0

What are the forecasts/targets for the PRTA price?
Analysts Target Price 21.4 117.7%
Prothena (PRTA) - Fundamental Data Overview as of 22 May 2026
Market Cap USD = 489.5m (489.5m USD * 1.0 USD.USD)
P/E Forward = 10.627
P/S = 8.4484
P/B = 1.5173
P/EG = 0.8
Revenue TTM = 57.9m USD
EBIT TTM = -84.0m USD
EBITDA TTM = -81.7m USD
Long Term Debt = 4.76m USD (estimated: total debt 7.65m - short term 2.89m)
Short Term Debt = 2.89m USD (from shortTermDebt, last quarter)
Debt = 7.65m USD (from shortLongTermDebtTotal, last quarter) (leases 7.65m already included)
Net Debt = -321.8m USD (calculated: Debt 7.65m - CCE 329.5m)
Enterprise Value = 167.7m USD (489.5m + Debt 7.65m - CCE 329.5m)
Interest Coverage Ratio = -3.81 (Ebit TTM -84.0m / Interest Expense TTM 22.0m)
EV/FCF = -2.06x (Enterprise Value 167.7m / FCF TTM -81.4m)
FCF Yield = -48.56% (FCF TTM -81.4m / Enterprise Value 167.7m)
 FCF Margin = -140.6% (FCF TTM -81.4m / Revenue TTM 57.9m)
 Net Margin = -260.9% (Net Income TTM -151.2m / Revenue TTM 57.9m)
 Gross Margin = 93.61% ((Revenue TTM 57.9m - Cost of Revenue TTM 3.70m) / Revenue TTM)
Gross Margin QoQ = none% (prev none%)
Tobins Q-Ratio = 0.48 (Enterprise Value 167.7m / Total Assets 349.9m)
 Interest Expense / Debt = 287.8% (Interest Expense 22.0m / Debt 7.65m)
 Taxrate = 0.00% (1.00k / 32.7m)
NOPAT = -84.0m (EBIT -84.0m * (1 - 0.00%)) [loss with tax shield]
Current Ratio = 10.43 (Total Current Assets 339.2m / Total Current Liabilities 32.5m)
Debt / Equity = 0.02 (Debt 7.65m / totalStockholderEquity, last quarter 312.6m)
 Debt / EBITDA = 3.94 (negative EBITDA) (Net Debt -321.8m / EBITDA -81.7m)
 Debt / FCF = 3.95 (negative FCF - burning cash) (Net Debt -321.8m / FCF TTM -81.4m)
 Total Stockholder Equity = 303.1m (last 4 quarters mean from totalStockholderEquity)
RoA = -35.77% (Net Income -151.2m / Total Assets 349.9m)
RoE = -9.35% (Net Income TTM -151.2m / Total Stockholder Equity 1.62b)
RoCE = -5.18% (EBIT -84.0m / Capital Employed (Equity 1.62b + L.T.Debt 4.76m))
 RoIC = -79.46% (negative operating profit) (NOPAT -84.0m / Invested Capital 105.7m)
 WACC = 11.10% (E(489.5m)/V(497.2m) * Re(11.27%) + (debt cost/tax rate unavailable))
Discount Rate = 11.27% (= CAPM, Blume Beta Adj.)
Shares (quarterly) Correlation: 67.42 | Cagr: 0.36%
 [DCF] Fair Price = unknown (Cash Flow -81.4m)
 EPS Correlation: N/A | EPS CAGR: N/A | SUE: 1.24 | # QB: 1
Revenue Correlation: -56.89 | Revenue CAGR: -50.66% | SUE: 1.16 | # QB: 1
EPS current Quarter (2026-06-30): EPS=0.38 | Chg30d=-71.32% | Revisions=+20% | Analysts=2
EPS next Quarter (2026-09-30): EPS=-0.30 | Chg30d=-13.21% | Revisions=+20% | Analysts=2
EPS current Year (2026-12-31): EPS=0.05 | Chg30d=-92.19% | Revisions=+33% | GrowthEPS=+101.3% | GrowthRev=+760.4%
EPS next Year (2027-12-31): EPS=-1.31 | Chg30d=-25.96% | Revisions=+20% | GrowthEPS=-2720.0% | GrowthRev=-73.6%
[Analyst] Revisions Ratio: +33%