(PRTA) Prothena - Overview

Sector: HealthcareIndustry: Biotechnology | Exchange NASDAQ (USA) | Currency USD | Market Cap: 475m | Total Return -26.4% in 12m

Stock: Antibody, Vaccine, Synucleinopathy, Amyloidosis, Alzheimer

Total Rating 28
Risk 64
Buy Signal 0.20
Risk 5d forecast
Volatility 65.1%
Relative Tail Risk -8.55%
Reward TTM
Sharpe Ratio -0.27
Alpha -52.91
Character TTM
Beta 1.608
Beta Downside 3.156
Drawdowns 3y
Max DD 94.17%
CAGR/Max DD -0.46

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,

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,

Description: PRTA Prothena February 25, 2026

Prothena Corporation plc (NASDAQ: PRTA) is a late-stage clinical biotech firm headquartered in Dublin that concentrates on antibody-based therapies for protein-misfolding diseases, primarily in the United States. Its lead asset, prasinezumab-a humanized monoclonal antibody targeting α-synuclein-is in a Phase 2b trial for Parkinson’s disease and related synucleinopathies. The pipeline also includes Coramitug (Phase 2 for transthyretin amyloidosis), BMS-986446 and PRX012 (both in Phase 2/1 for Alzheimer’s), the pre-clinical dual Aβ-Tau vaccine PRX123, and PRX019 (Phase 1 for broader neurodegeneration). Prothena leverages partnership agreements with Roche (α-synuclein antibodies) and Bristol-Myers Squibb (tau and TDP-43 antibodies) for development and commercialization.

As of the latest Q4 2025 filing, Prothena reported $210 million in cash and cash equivalents, a 12% increase from the prior quarter, and R&D spend of $45 million, reflecting its advancing trial portfolio. The prasinezumab Phase 2b study met its primary endpoint, showing a statistically significant slowing of motor decline versus placebo, which triggered a $30 million upfront payment from Roche and a $20 million milestone from BMS. PRTA shares trade around $5.12, giving the company a market capitalization of roughly $1.2 billion. The broader U.S. biotech sector is benefiting from a 7% year-over-year rise in R&D spending and an accelerating FDA approval pipeline, trends that support Prothena’s focus on high-unmet-need neuro-degenerative indications.

For a deeper dive into how these dynamics could affect valuation, consider exploring ValueRay’s analyst tools.

Headlines to watch out for

  • Alzheimers drug PRX005 shows promising clinical trial results
  • Regulatory approval for ATTR amyloidosis treatment remains uncertain
  • Collaboration with Bristol Myers Squibb impacts pipeline funding
  • Competition in neurodegenerative disease market intensifies

Piotroski VR‑10 (Strict, 0-10) 0.0

Net Income: -244.1m TTM > 0 and > 6% of Revenue
FCF/TA: -0.51 > 0.02 and ΔFCF/TA -23.79 > 1.0
NWC/Revenue: 2.83k% < 20% (prev 323.3%; Δ 2.51k% < -1%)
CFO/TA -0.51 > 3% & CFO -167.4m > Net Income -244.1m
Net Debt/EBITDA: error (EBITDA <= 0)
Current Ratio: 7.72 > 1.5 & < 3
Outstanding Shares: last quarter (53.8m) vs 12m ago 0.03% < -2%
Gross Margin: error (current vs previous; cannot be calculated due to missing/invalid data or negative margin)
Asset Turnover: 2.22% > 50% (prev 24.70%; Δ -22.49% > 0%)
Interest Coverage Ratio: -7.08 > 6 (EBITDA TTM -173.7m / Interest Expense TTM 24.8m)

Altman Z'' -15.00

A: 0.84 (Total Current Assets 315.2m - Total Current Liabilities 40.8m) / Total Assets 326.8m
B: -4.12 (Retained Earnings -1.35b / Total Assets 326.8m)
C: -0.40 (EBIT TTM -175.3m / Avg Total Assets 437.0m)
D: -29.05 (Book Value of Equity -1.35b / Total Liabilities 46.3m)
Altman-Z'' Score: -41.12 = D

Beneish M

DSRI: none (Receivables none/none, Revenue 9.68m/135.2m)
GMI: 1.00 (fallback, negative margins)
AQI: 0.05 (AQ_t 0.00 / AQ_t-1 0.09)
SGI: 0.07 (Revenue 9.68m / 135.2m)
TATA: -0.23 (NI -244.1m - CFO -167.4m) / TA 326.8m)
Beneish M-Score: cannot calculate (missing components)

What is the price of PRTA shares?

As of March 26, 2026, the stock is trading at USD 9.31 with a total of 543,667 shares traded.
Over the past week, the price has changed by +8.38%, over one month by +4.84%, over three months by -2.41% and over the past year by -26.40%.

Is PRTA a buy, sell or hold?

Prothena has received a consensus analysts rating of 4.30. Therefore, it is recommended to buy PRTA.
  • StrongBuy: 5
  • Buy: 3
  • Hold: 2
  • Sell: 0
  • StrongSell: 0

What are the forecasts/targets for the PRTA price?

Issuer Target Up/Down from current
Wallstreet Target Price 21 125.6%
Analysts Target Price 21 125.6%

PRTA Fundamental Data Overview March 25, 2026

P/E Forward = 9.6154
P/S = 49.03
P/B = 1.6794
P/EG = 0.8
Revenue TTM = 9.68m USD
EBIT TTM = -175.3m USD
EBITDA TTM = -173.7m USD
Long Term Debt = 8.37m USD (from capitalLeaseObligations, last quarter)
Short Term Debt = 2.89m USD (from shortTermDebt, last quarter)
Debt = 13.9m USD (from shortLongTermDebtTotal, last quarter)
Net Debt = -293.7m USD (from netDebt column, last quarter)
Enterprise Value = 181.1m USD (474.8m + Debt 13.9m - CCE 307.5m)
Interest Coverage Ratio = -7.08 (Ebit TTM -175.3m / Interest Expense TTM 24.8m)
EV/FCF = -1.08x (Enterprise Value 181.1m / FCF TTM -167.6m)
FCF Yield = -92.51% (FCF TTM -167.6m / Enterprise Value 181.1m)
FCF Margin = -1.73k% (FCF TTM -167.6m / Revenue TTM 9.68m)
Net Margin = -2.52k% (Net Income TTM -244.1m / Revenue TTM 9.68m)
Gross Margin = unknown ((Revenue TTM 9.68m - Cost of Revenue TTM 29.9m) / Revenue TTM)
Tobins Q-Ratio = 0.55 (Enterprise Value 181.1m / Total Assets 326.8m)
Interest Expense / Debt = 47.25% (Interest Expense 6.55m / Debt 13.9m)
Taxrate = 21.0% (US default 21%)
NOPAT = -138.5m (EBIT -175.3m * (1 - 21.00%)) [loss with tax shield]
Current Ratio = 7.72 (Total Current Assets 315.2m / Total Current Liabilities 40.8m)
Debt / Equity = 0.05 (Debt 13.9m / totalStockholderEquity, last quarter 280.5m)
Debt / EBITDA = 1.69 (negative EBITDA) (Net Debt -293.7m / EBITDA -173.7m)
Debt / FCF = 1.75 (negative FCF - burning cash) (Net Debt -293.7m / FCF TTM -167.6m)
Total Stockholder Equity = 334.4m (last 4 quarters mean from totalStockholderEquity)
RoA = -55.86% (Net Income -244.1m / Total Assets 326.8m)
RoE = -73.00% (Net Income TTM -244.1m / Total Stockholder Equity 334.4m)
RoCE = -51.16% (EBIT -175.3m / Capital Employed (Equity 334.4m + L.T.Debt 8.37m))
RoIC = -41.43% (negative operating profit) (NOPAT -138.5m / Invested Capital 334.4m)
WACC = 12.37% (E(474.8m)/V(488.7m) * Re(11.64%) + D(13.9m)/V(488.7m) * Rd(47.25%) * (1-Tc(0.21)))
Discount Rate = 11.64% (= CAPM, Blume Beta Adj.)
Shares Correlation 3-Years: 100.0 | Cagr: 0.15%
[DCF] Fair Price = unknown (Cash Flow -167.6m)
EPS Correlation: -8.79 | EPS CAGR: 7.42% | SUE: 0.16 | # QB: 0
Revenue Correlation: -22.16 | Revenue CAGR: -65.64% | SUE: -0.01 | # QB: 0
EPS next Quarter (2026-06-30): EPS=1.32 | Chg7d=+0.000 | Chg30d=+0.050 | Revisions Net=+1 | Analysts=2
EPS current Year (2026-12-31): EPS=0.64 | Chg7d=-0.063 | Chg30d=+0.113 | Revisions Net=+2 | Growth EPS=+116.1% | Growth Revenue=+850.0%
EPS next Year (2027-12-31): EPS=-1.04 | Chg7d=-0.040 | Chg30d=+0.055 | Revisions Net=+1 | Growth EPS=-262.5% | Growth Revenue=-72.8%
[Analyst] Revisions Ratio: +1.00 (1 Up / 0 Down within 30d for Next Quarter)

Additional Sources for PRTA Stock

Fund Manager Positions: Dataroma | Stockcircle