PRTA

Company Overview — What Does PROTHENA CORP PUBLIC LTD CO Do?

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 the treatment of Transthyretin amyloidosis; and PRX005, which is in Phase I clinical trial for the treatment of Alzheimer's disease. Its discovery and preclinical programs include PRX012 for the treatment of Alzheimer's disease; and dual Aß-Tau vaccine for the treatment and prevention of Alzheimer's disease. Prothena Corporation plc has a license, development, and commercialization agreement with F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. to develop and commercialize antibodies that target alpha-synuclein; and a collaboration agreement with Bristol-Myers Squibb to develop antibodies. The company was founded in 2012 and is based in Dublin, Ireland. PROTHENA CORP PUBLIC LTD CO (PRTA) is classified as a small-cap stock in the Healthcare sector, specifically within the Pharmaceutical Products industry. The company is led by CEO Gene G. Kinney and employs approximately 130 people. With a market capitalization of $540M, PRTA is one of the notable companies in the Healthcare sector.

PROTHENA CORP PUBLIC LTD CO (PRTA) Stock Rating — Reduce (April 2026)

As of April 2026, PROTHENA CORP PUBLIC LTD CO receives a Reduce rating with a composite score of 27.6/100 and 2 out of 5 stars from the Blank Capital Research quantitative model.PRTA ranks #2,575 out of 4,446 stocks in our coverage universe. Within the Healthcare sector, PROTHENA CORP PUBLIC LTD CO ranks #335 of 838 stocks, placing it in the upper half of its Healthcare peers. The rating is generated by a multi-factor model that weighs quality (30%), momentum (25%), value (15%), investment (10%), stability (10%), and short interest (10%).

PRTA Stock Price and 52-Week Range

PROTHENA CORP PUBLIC LTD CO (PRTA) currently trades at $10.50. The stock lost $0.08 (0.8%) in the most recent trading session. The 52-week high for PRTA is $13.71, which means the stock is currently trading -23.4% from its annual peak. The 52-week low is $4.32, putting the stock 143.1% above its annual trough. Recent trading volume was 319K shares, suggesting relatively thin trading activity.

Is PRTA Overvalued or Undervalued? — Valuation Analysis

PROTHENA CORP PUBLIC LTD CO (PRTA) carries a value factor score of 15/100 in the Blank Capital model, signaling premium valuation that prices in significant future growth. The price-to-book ratio stands at 1.99x, versus the sector average of 2.75x. The price-to-sales ratio is 52.45x, compared to 1.66x for the average Healthcare stock.

At current multiples, PROTHENA CORP PUBLIC LTD CO trades at a premium to most Healthcare peers. This elevated valuation may be justified if the company can sustain above-average growth rates and profitability, but it also creates downside risk if earnings disappoint expectations.

PROTHENA CORP PUBLIC LTD CO Profitability — ROE, Margins, and Quality Score

PROTHENA CORP PUBLIC LTD CO (PRTA) earns a quality factor score of 25/100, signaling below-average profitability metrics relative to the broader market. The return on equity (ROE) is -100.4%, compared to the Healthcare sector average of -43.5%, which is below typical expectations for high-quality companies. Return on assets (ROA) comes in at -86.1% versus the sector average of -33.1%.

On a margin basis, PROTHENA CORP PUBLIC LTD CO reports gross margins of 100.0%, compared to 71.5% for the sector. The operating margin is -3189.2% (sector: -66.1%). Net profit margin stands at -3142.4%, versus -58.7% for the average Healthcare stock. Revenue growth is running at -98.2% on a trailing basis, compared to 10.6% for the sector. Profitability is below benchmark levels, which may reflect industry headwinds, elevated reinvestment, or structural challenges.

PRTA Debt, Balance Sheet, and Financial Health

PROTHENA CORP PUBLIC LTD CO has a debt-to-equity ratio of 17.0%, compared to the Healthcare sector average of 32.0%. The low leverage indicates a conservative balance sheet with significant financial flexibility. The current ratio is 7.72x, indicating strong short-term liquidity. Total debt on the balance sheet is $0. Cash and equivalents stand at $331M.

PRTA has a beta of 0.56, meaning it is less volatile than the S&P 500, making it a relatively defensive holding. The stability factor score for PROTHENA CORP PUBLIC LTD CO is 50/100, reflecting average volatility within the normal range for its sector.

PROTHENA CORP PUBLIC LTD CO Revenue and Earnings History — Quarterly Trend

In TTM 2026, PROTHENA CORP PUBLIC LTD CO reported revenue of $11M and earnings per share (EPS) of $-4.53. Net income for the quarter was $-282M. Gross margin was 100.0%. Operating income came in at $-257M.

In FY 2025, PROTHENA CORP PUBLIC LTD CO reported revenue of $10M and earnings per share (EPS) of $-4.53. Net income for the quarter was $-244M. Revenue grew -92.8% year-over-year compared to FY 2024. Operating income came in at $-215M.

In Q3 2025, PROTHENA CORP PUBLIC LTD CO reported revenue of $2M and earnings per share (EPS) of $-0.68. Net income for the quarter was $-37M. Revenue grew 149.0% year-over-year compared to Q3 2024. Operating income came in at $-40M.

In Q2 2025, PROTHENA CORP PUBLIC LTD CO reported revenue of $4M and earnings per share (EPS) of $-2.34. Net income for the quarter was $-126M. Revenue grew -96.7% year-over-year compared to Q2 2024. Operating income came in at $-85M.

Over the past 8 quarters, PROTHENA CORP PUBLIC LTD CO has experienced revenue contraction from $132M to $11M. Investors analyzing PRTA stock should weigh these quarterly trends alongside the valuation and quality metrics discussed above.

PRTA Dividend Yield and Income Analysis

PROTHENA CORP PUBLIC LTD CO (PRTA) does not currently pay a dividend. This is common among smaller companies in the Pharmaceutical Products industry that prefer to reinvest cash flows into business expansion rather than returning capital to shareholders. Income-focused investors looking for Healthcare dividend stocks may want to explore other Healthcare stocks or use the stock screener to filter by dividend yield.

PRTA Momentum and Technical Analysis Profile

PROTHENA CORP PUBLIC LTD CO (PRTA) has a momentum factor score of 35/100, signaling weak relative price performance. Stocks with low momentum scores have historically tended to continue underperforming in the near term. The investment factor score is 40/100, which measures capital allocation efficiency and asset growth patterns. The short interest score of 1/100 signals elevated short interest, which can indicate bearish sentiment among institutional investors.

PRTA vs Competitors — Healthcare Sector Ranking and Peer Comparison

Within the Healthcare sector, PROTHENA CORP PUBLIC LTD CO (PRTA) ranks #335 out of 838 stocks based on the Blank Capital composite score. This places PRTA in the upper half of all Healthcare stocks in our coverage universe. Key competitors and sector peers include ASTRAZENECA PLC (AZN) with a score of 61.4/100, Sol-Gel Technologies Ltd. (SLGL) with a score of 56.6/100, VIEMED HEALTHCARE, INC. (VMD) with a score of 53.4/100, Innoviva, Inc. (INVA) with a score of 52.7/100, and JOHNSON & JOHNSON (JNJ) with a score of 51.7/100.

Comparing PRTA against the S&P 500 benchmark is also instructive for understanding relative performance. Investors can view the full PRTA vs S&P 500 (SPY) comparison to assess how PROTHENA CORP PUBLIC LTD CO stacks up against the broader market across all factor dimensions.

PRTA Next Earnings Date

No upcoming earnings date has been announced for PROTHENA CORP PUBLIC LTD CO (PRTA) at this time. Check the earnings calendar for the latest scheduling updates across all stocks in our coverage universe.

Should You Buy PRTA? — Investment Thesis Summary

The quantitative profile for PROTHENA CORP PUBLIC LTD CO suggests caution. The quality score of 25/100 flags below-average profitability. The value score of 15/100 indicates premium valuation. Momentum is weak at 35/100, a headwind for near-term performance.

In summary, PROTHENA CORP PUBLIC LTD CO (PRTA) earns a Reduce rating with a composite score of 27.6/100 as of April 2026. The rating is derived from the Blank Capital Research methodology, which combines six factor dimensions into a single quantitative ranking. Investors should consider these quantitative signals alongside their own fundamental research, risk tolerance, and investment time horizon before making buy or sell decisions on PRTA stock.

Related Resources for PRTA Investors

Explore more research and tools: PRTA vs S&P 500 comparison, top Healthcare stocks, stock screener, our methodology, quality factor explained, value factor explained, momentum factor explained. Compare PRTA head-to-head with peers: PRTA vs AZN, PRTA vs SLGL, PRTA vs VMD.