Prothena (PRTA) Stock Price, News & Analysis

Company Overview

Prothena Corporation plc is a clinical-stage biotechnology company focused on discovering and developing therapies for diseases caused by protein misfolding or abnormal protein accumulation. Its research programs target neurological and systemic disorders, including Alzheimer’s disease, Parkinson’s disease, and transthyretin amyloidosis.

The company’s pipeline has included PRX012, an investigational next-generation antibody targeting amyloid beta for Alzheimer’s disease; prasinezumab, an anti-alpha-synuclein antibody being developed for Parkinson’s disease through a collaboration with Roche; and birtamimab, an investigational treatment designed to target misfolded light chains associated with AL amyloidosis. These candidates remain subject to clinical testing and regulatory review, and Prothena does not have a broad portfolio of commercially marketed products.

Prothena was established in 2012 following the separation of neuroscience assets from Elan Corporation. The company is incorporated in Ireland and conducts research and development through operations and partnerships serving international markets. Its business model centers on applying expertise in protein biology and antibody development to create potential treatments for serious diseases with limited therapeutic options.

Key Stats

• Today's Range: $7.91 to $8.37
• 50-Day Range: $8.12 to $9.82
• 52-Week Range: $7.73 to $11.80
• Volume: 501,329 shs
• Average Volume: 507,059 shs
• Market Capitalization: $432.93 million
• P/E Ratio: N/A
• Dividend Yield: N/A
• Price Target: $24.57
• Consensus Rating: Moderate Buy

Prothena Stock Analysis - MarketRank™

Prothena scored higher than 63% of companies evaluated by MarketBeat, and ranked 304th out of 888 stocks in the healthcare sector. Scores are calculated by averaging available category scores, with extra weight given to analysis and valuation.

Analyst's Opinion

• Score: 4.0 / 5
• Analyst Rating: Moderate Buy

Consensus Rating

Prothena has received a consensus rating of Moderate Buy. The company's average rating score is 2.75, and is based on 1 strong buy rating, 5 buy ratings, 1 hold rating, and 1 sell rating.

Upside Potential

Prothena has a consensus price target of $24.57, representing about 197.4% upside from its current price of $8.26.

Amount of Analyst Coverage

Prothena has only been the subject of 3 research reports in the past 90 days.

Earnings and Valuation

• Score: 0.0 / 5
• Proj. Earnings Growth: Decreasing

Earnings Growth

Earnings for Prothena are expected to decrease in the coming year, from $0.08 to ($1.13) per share.

Price to Earnings Ratio vs. the Market

The P/E ratio of Prothena is -9.86, which means that its earnings are negative and its P/E ratio cannot be compared to companies with positive earnings.

Price to Earnings Ratio vs. Sector

The P/E ratio of Prothena is -9.86, which means that its earnings are negative and its P/E ratio cannot be compared to companies with positive earnings.

Price to Earnings Growth Ratio

Prothena has a PEG Ratio of 2.95. PEG Ratios above 1 indicate that a company could be overvalued.

Price to Book Value per Share Ratio

Prothena has a P/B Ratio of 1.59. P/B Ratios below 3 indicates that a company is reasonably valued with respect to its assets and liabilities.

Short Interest

• Score: 0.0 / 5
• Short Interest Level: Bearish

Percentage of Shares Shorted

18.22% of the float of Prothena has been sold short.

Short Interest Ratio / Days to Cover

Prothena has a short interest ratio ("days to cover") of 26.53, which indicates bearish sentiment.

Change versus previous month

Short interest in Prothena has recently increased by 0.58%, indicating that investor sentiment is decreasing.

Dividend

• Score: 0.0 / 5
• Dividend Strength: N/A

Dividend Yield

Prothena does not currently pay a dividend.

Dividend Growth

Prothena does not have a long track record of dividend growth.

News and Social Media

• Score: 3.8 / 5
• News Sentiment: 1.06

News Sentiment

Prothena has a news sentiment score of 1.06. This score is calculated as an average of sentiment of articles about the company over the last seven days and ranges from 2 (good news) to -2 (bad news). This is a higher news sentiment than the 0.43 average news sentiment score of Healthcare companies.

News Coverage This Week

MarketBeat has tracked 10 news articles for Prothena this week, compared to 2 articles on an average week.

MarketBeat Follows

4 people have added Prothena to their MarketBeat watchlist in the last 30 days. This is an increase of 33% compared to the previous 30 days.

Company Ownership

• Score: 3.9 / 5
• Insider Trading: Acquiring Shares

Net Insider Buying

Over the last three months, insiders have purchased a net $3,698,523.00 in company stock, which represents 0.8550% of the company's market cap.

Insider Buying vs. Insider Selling

In the past three months, Prothena insiders have bought 2,720.96% more of their company's stock than they have sold. Specifically, they have bought $3,834,450.00 in company stock and sold $135,927.00 in company stock.

Percentage Held by Insiders

10.40% of the stock of Prothena is held by insiders. A high percentage of insider ownership can be a sign of company health.

Percentage Held by Institutions

97.08% of the stock of Prothena is held by institutions. High institutional ownership can be a signal of strong market trust in this company.

Company Calendar

• Last Earnings: 8/06/2026
• Today: 10/05/2026
• Next Earnings (Estimated): 11/05/2026
• Fiscal Year End: 12/31/2026

Industry, Sector and Symbol

• Stock Exchange: NASDAQ
• Sector: Healthcare
• Industry: Biotechnology
• Sub-Industry: Biotechnology
• Current Symbol: NASDAQ:PRTA
• CIK: 1559053
• Web: www.prothena.com
• Phone: (531) 236-2500
• Fax: 353-1902-3510
• Employees: 67
• Year Founded: 2012

Price Target and Rating

• Average Price Target for Prothena: $24.57
• High Price Target: $36.00
• Low Price Target: $12.00
• Potential Upside/Downside: +198.0%
• Consensus Rating: Moderate Buy
• Rating Score (0-4): 2.75
• Research Coverage: 8 Analysts

Profitability

• EPS (Trailing Twelve Months): ($0.84)
• Trailing P/E Ratio: N/A
• Forward P/E Ratio: 103.06
• P/E Growth: 2.95
• Net Income: -$244.09 million
• Net Margins: -80.68%
• Pretax Margin: -81.33%
• Return on Equity: -16.45%
• Return on Assets: -14.51%

Debt

• Debt-to-Equity Ratio: N/A
• Current Ratio: 25.05
• Quick Ratio: 25.05

Sales & Book Value

• Annual Sales: $9.68 million
• Price / Sales: 44.59
• Cash Flow: N/A
• Price / Cash Flow: N/A
• Book Value: $5.21 per share
• Price / Book: 1.58

Miscellaneous

• Outstanding Shares: 52,350,000
• Free Float: 46,908,000
• Market Cap: $431.63 million
• Optionable: Optionable
• Beta: -0.29