Prothena Corporation (PRTA) Stock Analysis & Winston Score

Prothena Corporation plc, a late-stage clinical company, focuses on discovery and development of novel therapies for life-threatening diseases in the United States. The company is involved in developing Birtamimab, an investigational humanized antibody that is in Phase III clinical trial for the treatment of AL amyloidosis; Prasinezumab, a humanized monoclonal antibody, which is in Phase IIb clinical trial for the treatment of Parkinson's disease; PRX004 that completed Phase I clinical trial for

Winston Score History

Growth Profile

For growth stock investors

When traditional metrics don't capture the full picture, these are the signals growth stock investors use instead.

Revenue Growth

>+1,000% YoY

YoY Growth Rate

Revenue accelerating

EPS Growth

+154.5% YoY

YoY Growth Rate

EPS growth accelerating

Insider Activity

11.8%ownership

→ Flat

Insiders holding steady — not selling despite ability to

Cash Position

Cash flow positive

$329M cash & investments

Quarterly Free Cash Flow

↓ Burn rate worsening

Company generates more cash than it spends — no dilution risk from fundraising

Revenue accelerating

Prothena Corporation grew revenue 1706% year-over-year and the growth rate is speeding up. That's the kind of momentum growth investors look for — the question is whether margins can follow.

The Winston Score above measures business quality today. Growth stocks often score lower because they invest in the future rather than maximising current profits. These metrics show what matters most for evaluating that future.

Score breakdown

Every number that matters to educated investors.

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Quality

Gross Margin

98.2%

Premium pricing power — 98.2% gross margin

Operating Margin

50.5%

Excellent — 50.5% operating margin

ROCE

8.1%

Below par — 8.1% return on capital

ROIC between 5% and 15%. They earn 5 to 15 cents back per year on every dollar invested.

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Growth

Sales YoY

-58.0%

Shrinking sales (-58.0% YoY)

EPS YoY

N/A

Data not available

EPS Consistency

2/8 quarters

Earnings rarely grow — volatile business

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Cash Flow

Cash Conversion

N/A

Data not available

FCF Margin

-140.6%

Burning cash (-140.6%)

Free cash flow is negative. They are burning cash, not generating it.

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Stability

Debt / Equity

0.02

Conservative — low debt load (0.02)

Interest Cover

N/A

—

Data not available

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Valuation

P/E Ratio (TTM)

N/M

no trend

Negative earnings — P/E not meaningful

P/E vs Forward

N/A

not available

Data not available

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Dividends

Not applicable for this business.

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