PRTA Stock Analysis: Prothena | NASDAQ

Biotechnology | NASDAQ, USA | Market Cap: 453m USD | 12M Return: 26.2% | Charts, Fundamentals & Technical Analysis

Parkinson Disease, Alzheimer Disease, Amyloidosis, ALS
Total Rating 30
Safety 50
Buy Signal -0.45
Biotechnology
Industry Rotation: +1.7
Market Cap: 453M
Avg Turnover: 5.06M
Risk 3d forecast
Volatility60.3%
VaR 5th Pctl9.87%
VaR vs Median-0.53%
Reward TTM
Sharpe Ratio0.63
Rel. Str. IBD19.2
Rel. Str. Peer Group13
Character TTM
Beta1.589
Beta Downside2.370
Hurst Exponent0.504
Drawdowns 3y
Max DD93.37%
CAGR/Max DD-0.53
CAGR/Mean DD-0.68
EPS (Earnings per Share) EPS (Earnings per Share) of PRTA over the last years for every Quarter: "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": -0.46, "2026-03": 0.68,
Last SUE: 1.21
Qual. Beats: 1
Revenue Revenue of PRTA over the last years for every Quarter: 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 Critical
Altman Z'' In Financial Distress Zone
Below Sma 200d

Tailwinds

No distinct edge detected

Seasonality 10.5 years of data

Jan -7.6% 29
Feb +1.3% 0
Mar -1.4% 2
Apr -5.4% 25
May -2.3% 14
Jun +6.7% 55
Jul +15.4% 26
Aug +0.2% 8
Sep -1.4% 8
Oct +2.2% 9
Nov -2.5% 24
Dec -7.0% 24

How good or bad each month usually is (without trend). The score below shows how much you can trust it: 0 = pure chance, >40 gets interesting and >55 is strong.

Description: PRTA Prothena

Prothena Corporation plc is an Ireland-based, late-stage clinical biotechnology company that develops therapies for diseases driven by protein dysregulation, a class of conditions that includes neurodegenerative and amyloid disorders. The companys pipeline spans Phase 3 through preclinical assets, led by Prasinezumab (a monoclonal antibody for Parkinsons disease and other synucleinopathies, partnered with Roche) and Coramitug (an antibody for transthyretin amyloidosis cardiomyopathy). Earlier-stage programs target tau and amyloid-beta in Alzheimers disease, TDP-43 in ALS, and other neurodegenerative indications, with several assets developed under a master collaboration with Bristol Myers Squibb.

Prothenas business model reflects a common approach among small-cap clinical-stage biotechs: it advances internally discovered antibody candidates through early and mid-stage development, then relies on licensing and co-development deals with larger pharmaceutical companies (Roche, Bristol Myers Squibb) to fund later-stage trials, manufacturing, and global commercialization. Incorporated in 2012 and listed on NASDAQ, the company carries meaningful clinical and regulatory risk typical of the biotechnology sub-industry, as its valuation is tied to trial outcomes rather than current product revenue.

Headlines to Watch Out For
  • Prasinezumab Phase 3 Parkinson data readout approaches
  • Coramitug Phase 3 ATTR amyloidosis trial results pending
  • Bristol Myers Squibb tau and TDP-43 collaboration drives milestone payments
Piotroski VR-10 (Strict) 0.0
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 97.40%; Δ -3.79% > 0.5%)
Asset Turnover: 13.71% > 50% (prev 27.85%; Δ -14.14% > 0%)
Interest Coverage Ratio: -2.66 > 6 (EBIT TTM -77.0m / Interest Expense TTM 29.0m)
Altman Z'' 1.09
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: -0.18 (EBIT TTM -77.0m / Avg Total Assets 422.6m)
D: 8.39 (Book Value of Equity 312.6m / Total Liabilities 37.3m)
Altman-Z'' = 1.09 = BB
What is the price of PRTA shares?

As of July 24, 2026, the stock is trading at USD 8.53 with a total of 532,211 shares traded. Over the past week, the price has changed by +0.71%, over one month by -10.68%, over three months by -20.50% and over the past year by +26.18%.

Current recommended Stop Loss: 7.90 (which is 7.4% or 1.4 ATR below the current price).

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 21.4 150.9%
Prothena (PRTA) - Fundamental Data Overview as of 20 July 2026
Market Cap USD = 453.4m (453.4m USD * 1.0 USD.USD)
P/E Forward = 10.627
P/S = 7.825
P/B = 1.4486
P/EG = 0.8
Revenue TTM = 57.9m USD
EBIT TTM = -77.0m USD
EBITDA TTM = -74.7m 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 = 131.6m USD (453.4m + Debt 7.65m - CCE 329.5m)
Interest Coverage Ratio = -2.66 (Ebit TTM -77.0m / Interest Expense TTM 29.0m)
EV/FCF = -1.62x (Enterprise Value 131.6m / FCF TTM -81.4m)
FCF Yield = -61.90% (FCF TTM -81.4m / Enterprise Value 131.6m)
 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 = 0.38 (Enterprise Value 131.6m / Total Assets 349.9m)
 Interest Expense / Debt = 378.3% (Interest Expense 29.0m / Debt 7.65m)
 Taxrate = 0.00% (1.00k / 32.7m)
NOPAT = -77.0m (EBIT -77.0m * (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 = 4.31 (negative EBITDA) (Net Debt -321.8m / EBITDA -74.7m)
 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 = -49.88% (Net Income TTM -151.2m / Total Stockholder Equity 303.1m)
RoCE = -25.02% (EBIT -77.0m / Capital Employed (Equity 303.1m + L.T.Debt 4.76m))
 RoIC = -24.27% (negative operating profit) (NOPAT -77.0m / Invested Capital 317.4m)
 WACC = 11.38% (E(453.4m)/V(461.0m) * Re(11.57%) + (debt cost/tax rate unavailable))
Discount Rate = 11.57% (= CAPM, Blume Beta Adj.)
Shares (quarterly) Correlation: -5.26 | Cagr: 0.36%
 [DCF] Fair Price = unknown (Cash Flow -81.4m)
 EPS Correlation: N/A | EPS CAGR: N/A | SUE: 1.21 | # 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=+25% | Analysts=2
EPS next Quarter (2026-09-30): EPS=-0.30 | Chg30d=-13.21% | Revisions=+25% | Analysts=2
EPS current Year (2026-12-31): EPS=0.05 | Chg30d=-92.19% | Revisions=+40% | GrowthEPS=+101.3% | GrowthRev=+760.4%
EPS next Year (2027-12-31): EPS=-1.31 | Chg30d=-25.96% | Revisions=+25% | GrowthEPS=-2720.0% | GrowthRev=-73.6%
[Analyst] Revisions Ratio: +62% (up=5, down=0)