PRTA Prothena Corporation plc - Ordinary Shares

NASDAQ · Biotechnology · View on SEC EDGAR ↗
$9.28
Price · May 20, 2026
Fundamentals as of May 7, 2026

PRTA Stock Snapshot Price, market cap, P/E, EPS, ROE, debt/equity, 52-week range

Price
$9.28
Market Cap
$514M
P/E (TTM)
-2.1
EPS (TTM)
$-4.53
Revenue (TTM)
$10M
Div Yield
ROE
-63.6%
Debt/Equity
52W Range
$4 – $12

PRTA Stock Price Chart Daily OHLCV with technical indicators — pan, zoom, and customize your view

10-Year Performance Revenue, net income, margins and EPS trends

Revenue & Net Income $10M
10-point trend, +817.9%
2016-12-31 2025-12-31
EPS $-4.53
7-point trend, -132.3%
2019-12-31 2025-12-31
Free Cash Flow
Margins -2520.6%

Valuation P/E, P/S, P/B, EV/EBITDA ratios — is the stock expensive or cheap?

Metric
5Y trend
PRTA
Peer Median
P/E (TTM)
5-point trend, -105.9%
-2.1
13.6
P/S (TTM)
5-point trend, +362.0%
53.1
3.0
P/B
5-point trend, -62.9%
1.8
1.8

Profitability Gross, operating and net margins; ROE, ROA, ROIC

Metric
5Y trend
PRTA
Peer Median
Operating Margin
5-point trend, -6277.4%
-2216.4%
Net Profit Margin
5-point trend, -7648.9%
-2520.6%
-47.4%
ROA
5-point trend, -493.1%
-55.9%
-13.0%
ROE
5-point trend, -408.7%
-63.6%
-18.4%
ROIC
5-point trend, -746.8%
-93.0%

Financial Health Debt, liquidity, solvency — balance sheet strength

Metric
5Y trend
PRTA
Peer Median
Current Ratio
5-point trend, -55.9%
7.7
3.7
Quick Ratio
5-point trend, -56.5%
7.5

Growth Revenue, EPS and net income growth: YoY, 3Y CAGR, 5Y CAGR

Metric
5Y trend
PRTA
Peer Median
Revenue YoY
5-point trend, -95.2%
-92.8%
Revenue CAGR 3Y
5-point trend, -95.2%
-43.6%
Revenue CAGR 5Y
5-point trend, -95.2%
62.6%

Per Share Metrics EPS, book value per share, cash flow per share, dividend per share

Metric
5Y trend
PRTA
Peer Median
EPS (Diluted)
5-point trend, -428.3%
$-4.53

Capital Efficiency Asset turnover, inventory turnover, receivables turnover

Metric
5Y trend
PRTA
Peer Median

PRTA Analyst Consensus Bullish and bearish analyst opinions, 12-month price target, upside

BUY 12 analysts
  • Strong Buy 2 16.7%
  • Buy 6 50.0%
  • Hold 3 25.0%
  • Sell 1 8.3%
  • Strong Sell 0 0.0%

12-Month Price Target

5 analysts · 2026-05-16
Median target $20.00 +115.6%
Mean target $21.40 +130.7%

Earnings History EPS actual vs estimate, surprise %, beat rate, next earnings date

Avg Surprise
0.13%
Period EPS Actual EPS Est Surprise
March 31, 2026 $0.61 $-0.36 0.97%
Dec. 31, 2025 $-0.40 $-0.57 0.17%
Sept. 30, 2025 $-0.68 $-0.70 0.02%
June 30, 2025 $-1.73 $-1.34 -0.39%
March 31, 2025 $-1.12 $-0.99 -0.13%

Peer Comparison Key metrics vs sector peers

Ticker Market Cap P/E Rev YoY Net Margin ROE Gross Margin
PRTA $514M -2.1 -92.8% -2520.6% -63.6%
ALKS $4.63B 19.6 -5.2% 16.4% 14.0%
AMRN $5.81B -155.1 -6.6% -18.2% -8.4% 56.6%

Full Fundamentals All metrics by year — income statement, balance sheet, cash flow

Income Statement 14
Annual Income Statement data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Revenue 12-point trend, -81.0% $10M $135M $91M $54M $201M $853.0K $814.0K $955.0K $28M $1M $2M $51M
R&D Expense 12-point trend, +250.7% $135M $223M $221M $136M $82M $75M $51M $101M $135M $120M $58M $38M
SG&A Expense 12-point trend, +211.8% $59M $67M $62M $50M $46M $39M $36M $42M $48M $41M $23M $19M
Operating Expenses 12-point trend, +290.1% $224M $290M $282M $185M $129M $114M $87M $160M $183M $161M $82M $58M
Operating Income 12-point trend, -3128.2% $-215M $-155M $-191M $-132M $72M $-113M $-86M $-159M $-155M $-160M $-80M $-7M
Other Non-op 12-point trend, -242.0% $-328.0K $-185.0K $-458.0K $-397.0K $-96.0K $-62.0K $196.0K $48.0K $-2M $15.0K $-170.0K $231.0K
Pretax Income 12-point trend, -3068.1% $-201M $-129M $-160M $-126M $72M $-111M $-77M $-156M $-158M $-159M $-80M $-6M
Income Tax 12-point trend, +5234.5% $43M $-7M $-13M $-9M $5M $-283.0K $379.0K $-470.0K $-4M $1M $701.0K $811.0K
Net Income 12-point trend, -3313.9% $-244M $-122M $-147M $-117M $67M $-111M $-78M $-156M $-153M $-160M $-81M $-7M
EPS (Basic) 7-point trend, -132.3% $-4.53 $-2.27 $-2.76 $-2.47 $1.51 $-2.78 $-1.95 · · · · ·
EPS (Diluted) 7-point trend, -132.3% $-4.53 $-2.27 $-2.76 $-2.47 $1.38 $-2.78 $-1.95 · · · · ·
Shares (Basic) 7-point trend, +35.0% 53,829,000 53,772,000 53,216,000 47,369,000 44,228,000 39,915,000 39,882,000 · · · · ·
Shares (Diluted) 7-point trend, +35.0% 53,829,000 53,772,000 53,216,000 47,369,000 48,464,000 39,915,000 39,882,000 · · · · ·
EBITDA 12-point trend, -3519.1% $-214M $-154M $-190M $-131M $73M $-111M $-84M $-156M $-152M $-157M $-79M $-6M
Balance Sheet 21
Annual Balance Sheet data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Cash & Equivalents 12-point trend, +4.8% $308M $471M $619M $710M $579M $295M $376M $428M $418M $387M $371M $294M
Receivables 11-point trend, -100.0% · $0 $5M $0 $0 $15.0K $68.0K $2.0K $240.0K $178.0K $509.0K $2M
Prepaid Expense 12-point trend, +103.2% $8M $14M $14M $9M $6M $3M $3M $4M $8M $4M $6M $4M
Other Current Assets 2-point trend, -30.7% · · · · · · $3M $4M · · · ·
Current Assets 12-point trend, +5.4% $315M $485M $639M $719M $585M $299M $378M $431M $426M $391M $377M $299M
PP&E (Net) 12-point trend, -31.3% $2M $3M $4M $2M $2M $3M $4M $53M $55M $56M $4M $3M
PP&E (Gross) 12-point trend, +17.4% $9M $11M $11M $13M $12M $12M $12M $63M $63M $64M $9M $8M
Accum. Depreciation 12-point trend, +49.7% $7M $8M $7M $11M $10M $9M $8M $11M $8M $8M $5M $5M
Other Non-current Assets 12-point trend, +482000.00 $482.0K $4M $6M $11M $2M $333.0K $1M $813.0K $3M $2M $1M $0
Total Assets 12-point trend, +7.5% $327M $547M $696M $758M $609M $333M $419M $499M $496M $460M $385M $304M
Accounts Payable 12-point trend, +24.4% $6M $8M $25M $9M $4M $4M $1M $1M $14M $13M $5M $5M
Current Liabilities 12-point trend, +239.3% $41M $49M $57M $50M $33M $26M $18M $15M $37M $41M $22M $12M
Capital Leases 8-point trend, +5487000.00 $5M $8M $11M $0 $6M $12M $18M $0 · · · ·
Other Non-current Liabilities 10-point trend, +0.00 · · $0 $553.0K $553.0K $553.0K $553.0K $553.0K $0 $0 $126.0K $0
Total Liabilities 12-point trend, +225.6% $46M $60M $135M $136M $143M $149M $146M $176M $89M $95M $25M $14M
Common Stock 12-point trend, +96.4% $538.0K $538.0K $537.0K $521.0K $466.0K $399.0K $399.0K $399.0K $385.0K $348.0K $317.0K $274.0K
Paid-in Capital 12-point trend, +381.0% $1.63B $1.59B $1.54B $1.45B $1.18B $967M $944M $921M $849M $654M $489M $338M
Retained Earnings 12-point trend, -2676.7% $-1.35B $-1.10B $-980M $-833M $-716M $-783M $-672M $-598M $-442M $-289M $-129M $-48M
Stockholders' Equity 12-point trend, -3.2% $280M $487M $561M $622M $466M $184M $273M $323M $407M $365M $361M $290M
Liabilities + Equity 12-point trend, +7.5% $327M $547M $696M $758M $609M $333M $419M $499M $496M $460M $385M $304M
Shares Outstanding 12-point trend, +96.6% 53,832,982 53,826,982 53,682,117 52,103,608 46,660,294 39,921,413 39,898,561 39,863,711 38,482,764 34,752,116 31,744,102 27,388,005
Cash Flow 12
Annual Cash Flow data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
D&A 12-point trend, +20.5% $895.0K $893.0K $928.0K $744.0K $1M $2M $2M $3M $3M $2M $806.0K $743.0K
Stock-based Comp 12-point trend, +572.5% $38M $46M $41M $31M $25M $22M $24M $27M $27M $25M $10M $6M
Deferred Tax 12-point trend, +4237.7% $43M $-9M $-16M $-11M $5M $-2M $-1M $-2M $-2M $-3M $-963.0K $-1M
Restructuring 2-point trend, -100.4% · · · · · · $-61.0K $15M · · · ·
Other Non-cash 12-point trend, -207.7% $-1M $-65M $-13M $-13M $-5M $9M $808.0K $99M $-6M $19M $8M $1M
Operating Cash Flow 12-point trend, -23850.2% $-164M $-150M $-134M $-109M $93M $-80M $-53M $-28M $-131M $-116M $-59M $-683.0K
Investing Cash Flow 12-point trend, +72.3% $-138.0K $-298.0K $-3M $-464.0K $-575.0K $-196.0K $-547.0K $-2M $-4M $-17M $-1M $-499.0K
Stock Issued 8-point trend, -33.5% · · · · $78M $0 $0 $0 $150M $129M $131M $117M
Net Stock Activity 7-point trend, -33.5% · · · · $78M · $0 $0 $150M $129M $131M $117M
Financing Cash Flow 12-point trend, -100.1% $-139.0K $2M $45M $241M $190M $215.0K $228.0K $40M $165M $153M $137M $118M
Net Change in Cash 2-point trend, -34.1% · · · · · · · · · · $77M $117M
Taxes Paid 9-point trend, +216.7% $931.0K $3M $2M $3M $580.0K $1M $2M $-995.0K $294.0K · · ·
Profitability 7
Annual Profitability data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Operating Margin 12-point trend, -16858.2% -2216.4% -114.4% -209.1% -244.1% 35.9% -13216.2% -10527.9% -16634.0% -564.2% -15121.8% -4974.3% -13.1%
Net Margin 12-point trend, -17827.2% -2520.6% -90.5% -160.9% -217.0% 33.4% -13029.8% -9542.6% -16297.9% -556.8% -15176.1% -5016.3% -14.1%
Pretax Margin 12-point trend, -16530.5% -2073.8% -95.4% -175.6% -233.0% 35.9% -13063.0% -9496.1% -16347.1% -572.7% -15067.7% -4972.7% -12.5%
EBITDA Margin 12-point trend, -18911.2% -2207.2% -113.7% -208.1% -242.7% 36.4% -13038.7% -10335.8% -16297.3% -553.0% -14891.7% -4924.1% -11.6%
ROA 12-point trend, -1800.0% -55.9% -19.7% -20.2% -17.1% 14.2% -29.5% -16.9% -31.3% -32.0% -37.9% -23.4% -2.9%
ROE 12-point trend, -1958.9% -63.6% -23.3% -24.9% -21.5% 20.6% -48.6% -26.1% -42.6% -39.7% -44.1% -24.8% -3.1%
ROIC 12-point trend, -3491.1% -93.0% -30.1% -31.2% -19.7% 14.4% -61.1% -31.6% -49.0% -37.1% -44.0% -22.4% -2.6%
Liquidity & Solvency 2
Annual Liquidity & Solvency data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Current Ratio 12-point trend, -69.0% 7.7 10.0 11.2 14.3 17.5 11.6 21.4 28.9 11.4 9.5 17.0 24.9
Quick Ratio 12-point trend, -69.3% 7.5 9.7 11.0 14.2 17.3 11.4 21.2 28.7 11.2 9.4 16.7 24.5
Efficiency 2
Annual Efficiency data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Asset Turnover 12-point trend, -89.4% 0.0 0.2 0.1 0.1 0.4 0.0 0.0 0.0 0.1 0.0 0.0 0.2
Receivables Turnover 10-point trend, -10.9% · 52.4 35.4 · 26743.6 20.6 23.3 7.9 131.7 3.1 1.4 58.8
Per Share 5
Annual Per Share data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Book Value / Share 12-point trend, -50.8% $5.21 $9.05 $10.46 $11.94 $9.99 $4.61 $6.84 $8.10 $10.58 $10.51 $11.36 $10.58
Revenue / Share 5-point trend, -95.7% $0.18 $2.51 $1.72 $1.14 $4.14 · · · · · · ·
Cash Flow / Share 5-point trend, -259.0% $-3.04 $-2.79 $-2.52 $-2.30 $1.91 · · · · · · ·
Cash / Share 12-point trend, -46.7% $5.71 $8.76 $11.53 $13.63 $12.41 $7.40 $9.42 $10.73 $10.85 $11.13 $11.67 $10.72
EPS (TTM) 12-point trend, -3675.0% $-4.53 $-2.27 $-2.76 $-2.47 $1.38 $-2.78 $-1.95 $-3.94 $-4.06 $-4.66 $-2.63 $-0.12
Growth Rates 3
Annual Growth Rates data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Revenue YoY 5-point trend, -100.4% -92.8% 47.9% 69.5% -73.1% 23414.3% · · · · · · ·
Revenue CAGR 3Y 3-point trend, -111.6% -43.6% -12.3% 374.9% · · · · · · · · ·
Revenue CAGR 5Y 62.6% · · · · · · · · · · ·
Valuation (TTM) 9
Annual Valuation (TTM) data for PRTA
Metric Trend 202520242023202220212020201920182017201620152014
Revenue TTM 12-point trend, -81.0% $10M $135M $91M $54M $201M $853.0K $814.0K $955.0K $28M $1M $2M $51M
Net Income TTM 12-point trend, -3313.9% $-244M $-122M $-147M $-117M $67M $-111M $-78M $-156M $-153M $-160M $-81M $-7M
Market Cap 12-point trend, -9.6% $514M $746M $1.95B $3.14B $2.31B $479M $632M $411M $1.44B $1.71B $2.16B $569M
P/E 12-point trend, +98.8% -2.1 -6.1 -13.2 -24.4 35.8 -4.3 -8.1 -2.6 -9.2 -10.6 -25.9 -173.0
P/S 12-point trend, +374.8% 53.1 5.5 21.4 58.2 11.5 562.1 775.9 429.9 52.4 1620.3 1345.4 11.2
P/B 12-point trend, -6.5% 1.8 1.5 3.5 5.0 4.9 2.6 2.3 1.3 3.5 4.7 6.0 2.0
P / Tangible Book 6-point trend, -29.7% 1.8 1.5 3.5 5.0 4.9 2.6 · · · · · ·
P / Cash Flow 12-point trend, +99.6% -3.1 -5.0 -14.6 -28.8 24.9 -6.0 -11.9 -14.5 -11.0 -14.6 -34.6 -832.5
Earnings Yield 12-point trend, -8077.6% -47.4% -16.4% -7.6% -4.1% 2.8% -23.2% -12.3% -38.2% -10.8% -9.5% -3.9% -0.58%

Financial Statements Income statement, balance sheet, cash flow — annual, last 5 years

Income Statement
2025-12-312024-12-312023-12-312022-12-312021-12-31
Revenue $10M$135M$91M$54M$201M
Operating Margin % -2216.4%-114.4%-209.1%-244.1%35.9%
Net Income $-244M$-122M$-147M$-117M$67M
Diluted EPS $-4.53$-2.27$-2.76$-2.47$1.38
Balance Sheet
2025-12-312024-12-312023-12-312022-12-312021-12-31
Current Ratio 7.710.011.214.317.5
Quick Ratio 7.59.711.014.217.3

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