PRTA Healthcare

Prothena Corporation plc

$8.21-0.97%

Price as of close on Nov 3, 2026 · Financials updated Sep 30, 2026

Basics

Sector: Healthcare
Industry: Biotechnology
Country: Ireland
Market cap: 421.5M USD
Enterprise value: 160.8M USD
Full-time employees: 67

Overall health

Strength: growing faster than most peersgrowing faster than peers
Strength: lower risk than most peers: more short-term liquidity and less debt relative to equitylower risk: more liquidity and less debt vs equity
Drawback: less profitable than most peersless profitable than peers
Drawback: its shares are priced higher than most peers relative to what it earnspriced higher than peers for its earnings

Ranks #576 of 1,157 healthcare companies (top 50%)

See how it ranks against its peers

Worth knowing

Stock-based pay is a large cost. Stock pay was 389% of revenue in 2025.
Prothena paid employees $38M in stock in 2025, 389% of its $10M revenue. It doesn't use cash, so it flatters cash flow, but it is a real cost to shareholders through dilution.
Valuation signals disagree. Cheaper than 50% of peers on free cash flow, but only 0% on earnings.
Relative to its free cash flow, Prothena looks cheaper than 50% of peers; relative to its earnings, cheaper than only 0%. The valuation score blends the two, so look at which measure fits this business best.
Growing fast, still losing money. Revenue grew faster than 95% of peers, at an operating loss.
Revenue grew faster than 95% of peers, but the business runs at an operating loss (margin -102%).

StockQuotient Score

52/ 100

Oct 5 52 → Nov 4 52

Valuation

Is the price right?

8/100

Weak

3/3 inputs reported · High confidence

Since last quarter: No major changeValuation also moves with the share price every day.

Why

Weaker than most peers on:

▼ Earnings yield
▼ EBITDA yield

Compare with peers

Behind the score

Sector-normalized EBITDA, earnings, and free cash flow yields.

Earnings yield-10.4%

SEC filings · 12 months to Jun 2026Negative (a loss or cash outflow), so it counts as zero whatever the share price30% base weight · Z-score -1.00Sector median: 0.0148 · MAD: 0.0148

EBITDA yield-36.7%

Yahoo Finance fallback · SEC enterprise value unavailable (debt or EBITDA not reported in standard form) · trailing 12 monthsNegative (a loss or cash outflow), so it counts as zero whatever the share price50% base weight · Z-score -1.00Sector median: 0.0401 · MAD: 0.0401

Free cash flow yield-14.4%

Yahoo Finance fallback · SEC cash flow or share count unavailable · trailing 12 months · operating cash flow − capital spendingNegative (a loss or cash outflow), so it counts as zero whatever the share price20% base weight · Z-score 0.00Sector median: 0.0000 · MAD: 0.0000

Other data (not scored)

Book yield68.1%

SEC filings · latest balance sheetReported valueInformational · 0% composite weightSector median: 0.3716 · MAD: 0.2313

Growth

Is it growing?

88/100

Strong

3/3 inputs reported · High confidence

Since last quarter: ▼ Weaker

12-month revenue fell 5.9%

Why

Stronger than most peers on:

▲ Revenue growth

Compare with peers

Behind the score

Revenue and earnings-per-share growth over one year, and revenue growth over three years.

Earnings per share growthUnavailable

Still loss-making, but the loss per share narrowed33% base weight · Z-score 0.29Sector median: 0.0976 · MAD: 0.2991

3-year revenue growth-1.8%

SEC filings · 3 years to Jun 2026Reported value33% base weight · Z-score -0.91Sector median: 0.0584 · MAD: 0.0840

Revenue growth427.3%

SEC filings · 12 months to Jun 2026Outlier capped at sector 5th/95th percentile33% base weight · Z-score 10.15Sector median: 0.0609 · MAD: 0.0974

Profitability

Does it earn well?

12/100

Weak

3/3 inputs reported · High confidence

Since last quarter: No major change

Why

Weaker than most peers on:

▼ ROIC
▼ Operating margin
▼ ROA

Compare with peers

Behind the score

Return on invested capital, operating margin, and return on assets.

Operating margin-101.8%

SEC filings · 12 months to Jun 2026Reported value33% base weight · Z-score -8.94Sector median: 0.0706 · MAD: 0.1217

Return on assets-14.5%

SEC filings · 12 months to Jun 2026Reported value33% base weight · Z-score -3.02Sector median: 0.0166 · MAD: 0.0537

Return on invested capital-23372.3%

Yahoo Finance fallback · SEC operating income or invested capital unavailable · trailing 12 monthsOutlier capped at sector 5th/95th percentile33% base weight · Z-score -16.87Sector median: 0.0471 · MAD: 0.1004

Other data (not scored)

Gross margin-19.1%

Yahoo Finance fallback · SEC figure unavailable or out of date · trailing 12 monthsOutlier capped at sector 5th/95th percentileInformational · 0% composite weightSector median: 0.4697 · MAD: 0.2310

Return on equity-15.3%

SEC filings · 12 months to Jun 2026Reported valueInformational · 0% composite weightSector median: 0.0330 · MAD: 0.1225

Risk

Debt, liquidity, price swings

Lower

Lower relative risk

2/3 inputs reported · Partial data

Since last quarter: No major change

Why

Stronger than most peers on:

▲ Current ratio
▲ Debt / equity

Compare with peers

Behind the score

Relative to sector peers: 0 = lower relative risk · 1 = moderate · 2 = higher. Based on leverage, beta and liquidity.

BetaUnavailable

Missing · left out of the score · no sector data, so not countedNot counted · remaining weights rescaledSector median: 0.6250 · MAD: 0.3380

Current ratio25.05×

SEC filings · latest balance sheetOutlier capped at sector 5th/95th percentile33% base weight · Z-score 11.07Sector median: 2.5860 · MAD: 1.3850

Debt / equity0.02×

Yahoo Finance fallback · no standard SEC debt tagReported value33% base weight · Z-score 0.97Sector median: 0.2215 · MAD: 0.2039

Valuation, growth and profitability scores: higher is better. Risk: 0 is lower, 2 is higher. Risk is a relative proxy, not a bankruptcy probability. Scores depend on available sector peers.

Questions investors ask about Prothena

Is Prothena getting weaker?: Its latest SEC filing (Aug 6, 2026) got weaker in some ways: 12-month revenue fell 5.9%. Its overall score is unchanged at 52/100 since Oct 28, 2026.
How is Prothena valued vs its peers?: Priced higher than most peers relative to what it earns. Valuation scores 8/100 against 1,393 healthcare peers. Earnings yield -10.4% vs a peer median of 1.5% (weaker than 100% of peers).Earnings yield -10.4% vs peers 1.5% (weaker than 100% of peers).
Is Prothena growing?: Yes, faster than most of its peers. Growth scores 88/100 against 1,393 healthcare peers. Revenue growth 427.3% vs a peer median of 6.1% (stronger than 95% of peers).Revenue growth 427.3% vs peers 6.1% (stronger than 95% of peers). 3-year revenue growth -1.8% vs a peer median of 5.8% (weaker than 76% of peers).3-year revenue growth -1.8% vs peers 5.8% (weaker than 76% of peers).
How profitable is Prothena?: Less profitable than most of its peers. Profitability scores 12/100 against 1,393 healthcare peers. Return on invested capital -23372.3% vs a peer median of 4.7% (weaker than 100% of peers).Return on invested capital -23372.3% vs peers 4.7% (weaker than 100% of peers).
How risky is Prothena?: Lower risk relative to 1,393 healthcare peers, judged on debt, liquidity and share-price swings. Current ratio 25.05× vs a peer median of 2.59× (stronger than 95% of peers).Current ratio 25.05× vs peers 2.59× (stronger than 95% of peers). A relative measure, not a bankruptcy probability.

Latest filing: what changed

Quarter ended Jun 30, 2026 · filed Aug 6, 2026 · compared with the quarter ended Mar 31, 2026

Got weaker

12-month revenue fell 5.9%

Worth watching: Prothena is in the bottom fifth of its sector on profitability. From 2021 to 2025, 63% of companies in that position posted a loss over the following year, against 4% for the top fifth.

	Previous quarter	Latest quarter	Change
Revenue (12 months)	57.9M USD	54.5M USD	−5.9%
Net income (12 months)	−151.2M USD	−44.0M USD	−70.9%
Operating margin	-205.4%	-101.8%	+103.6 pts
Cash	329.5M USD	288.2M USD	−12.5%
Shares outstanding	52.4M	51.3M	−1.9%

From the company’s own SEC filings, as filed. Twelve-month figures roll forward one quarter at a time.

Financials

Fiscal years from SEC annual filings · change vs the prior year

Key ratios	FY 2021	FY 2022	FY 2023	FY 2024	FY 2025	Change
Operating margin	35.9%	-244.1%	-209.1%	-114.4%	-2216.4%	▼ >999 pts
Net margin	33.4%	-217.0%	-160.9%	-90.5%	-2520.6%	▼ >999 pts
Return on assets (ROA)	11.0%	-15.4%	-21.1%	-22.4%	-74.7%	▼ 52 pts
Return on equity (ROE)	14.4%	-18.8%	-26.2%	-25.1%	-87.0%	▼ 62 pts
Current ratio	17.48×	14.34×	11.24×	10.01×	7.72×	▼ 23%

PRTA price history

Price history is added with the daily price update and will appear after the next one.

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Sector leaderboards

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Bringing the fundamentals into focus…

Overall health

Strength: growing faster than most peersgrowing faster than peers

Strength: lower risk than most peers: more short-term liquidity and less debt relative to equitylower risk: more liquidity and less debt vs equity

Drawback: less profitable than most peersless profitable than peers

Drawback: its shares are priced higher than most peers relative to what it earnspriced higher than peers for its earnings

Ranks #576 of 1,157 healthcare companies (top 50%)

See how it ranks against its peers

Worth knowing

Stock-based pay is a large cost. Stock pay was 389% of revenue in 2025.

Prothena paid employees $38M in stock in 2025, 389% of its $10M revenue. It doesn't use cash, so it flatters cash flow, but it is a real cost to shareholders through dilution.

Valuation signals disagree. Cheaper than 50% of peers on free cash flow, but only 0% on earnings.

Relative to its free cash flow, Prothena looks cheaper than 50% of peers; relative to its earnings, cheaper than only 0%. The valuation score blends the two, so look at which measure fits this business best.

Growing fast, still losing money. Revenue grew faster than 95% of peers, at an operating loss.

Revenue grew faster than 95% of peers, but the business runs at an operating loss (margin -102%).

Questions investors ask about Prothena

Is Prothena getting weaker?

Its latest SEC filing (Aug 6, 2026) got weaker in some ways: 12-month revenue fell 5.9%. Its overall score is unchanged at 52/100 since Oct 28, 2026.

How is Prothena valued vs its peers?

Priced higher than most peers relative to what it earns. Valuation scores 8/100 against 1,393 healthcare peers. Earnings yield -10.4% vs a peer median of 1.5% (weaker than 100% of peers).Earnings yield -10.4% vs peers 1.5% (weaker than 100% of peers).

Is Prothena growing?

Yes, faster than most of its peers. Growth scores 88/100 against 1,393 healthcare peers. Revenue growth 427.3% vs a peer median of 6.1% (stronger than 95% of peers).Revenue growth 427.3% vs peers 6.1% (stronger than 95% of peers). 3-year revenue growth -1.8% vs a peer median of 5.8% (weaker than 76% of peers).3-year revenue growth -1.8% vs peers 5.8% (weaker than 76% of peers).

How profitable is Prothena?

Less profitable than most of its peers. Profitability scores 12/100 against 1,393 healthcare peers. Return on invested capital -23372.3% vs a peer median of 4.7% (weaker than 100% of peers).Return on invested capital -23372.3% vs peers 4.7% (weaker than 100% of peers).

How risky is Prothena?

Lower risk relative to 1,393 healthcare peers, judged on debt, liquidity and share-price swings. Current ratio 25.05× vs a peer median of 2.59× (stronger than 95% of peers).Current ratio 25.05× vs peers 2.59× (stronger than 95% of peers). A relative measure, not a bankruptcy probability.

Previous quarter

Latest quarter

Change

Revenue (12 months)

57.9M USD

54.5M USD

−5.9%

Net income (12 months)

−151.2M USD

−44.0M USD

−70.9%

Operating margin

-205.4%

-101.8%

+103.6 pts

Cash

329.5M USD

288.2M USD

−12.5%

Shares outstanding

52.4M

51.3M

−1.9%

Key ratios

FY 2021

FY 2022

FY 2023

FY 2024

FY 2025

Change

Operating margin

35.9%

-244.1%

-209.1%

-114.4%

-2216.4%

▼ >999 pts

Net margin

33.4%

-217.0%

-160.9%

-90.5%

-2520.6%

▼ >999 pts

Return on assets (ROA)

11.0%

-15.4%

-21.1%

-22.4%

-74.7%

▼ 52 pts

Return on equity (ROE)

14.4%

-18.8%

-26.2%

-25.1%

-87.0%

▼ 62 pts

Current ratio

17.48×

14.34×

11.24×

10.01×

7.72×

▼ 23%