Prothena (PRTA) Stock Price, News & Analysis

Company Overview

Prothena Corporation plc is a clinical-stage biotechnology company focused on the discovery, development and commercialization of novel therapies for neurodegenerative and rare peripheral diseases. The company leverages its proprietary platform technologies to design and engineer monoclonal antibodies and small molecules that target disease-causing proteins. Core research activities center on immunotherapy approaches aimed at clearing or neutralizing pathological protein aggregates.

Prothena’s pipeline includes several lead assets in clinical development. PRX002/RG7935 is an anti–alpha-synuclein antibody being investigated for Parkinson’s disease, in collaboration with Roche. PRX004 is directed at serum amyloid A in patients with AA amyloidosis, while PRX012 targets interleukin-13 for the treatment of moderate-to-severe atopic dermatitis. The company also maintains a robust preclinical portfolio addressing other protein misfolding disorders and has partnered with industry leaders to advance select candidates into human trials.

Founded in 2012 as a spin-out from Elan Corporation, Prothena is headquartered in Dublin, Ireland, with research and development operations in South San Francisco. The company’s global footprint spans North America and Europe, enabling access to diverse patient populations and facilitating multinational clinical studies. Prothena’s integrated development infrastructure supports seamless progression from discovery through late-stage development.

Under the leadership of Chief Executive Officer Gene Kinney, Prothena is guided by a management team with extensive experience in biopharmaceutical development, regulatory strategy and commercial planning. With a focus on addressing high-unmet medical needs, the company aims to translate its scientific insights into first-in-class and best-in-class therapies for patients worldwide.

Key Stats

• Today's Range: $6.55 to $6.77
• 50-Day Range: $4.58 to $9.20
• 52-Week Range: $4.32 to $25.42
• Volume: 695,703 shs
• Average Volume: 800,699 shs
• Market Capitalization: $354.20 million
• P/E Ratio: N/A
• Dividend Yield: N/A
• Price Target: $31.50
• Consensus Rating: Hold

Prothena Stock Analysis - MarketRank™

Prothena scored higher than 61% of companies evaluated by MarketBeat, and ranked 384th out of 921 stocks in the medical sector. Scores are calculated by averaging available category scores, with extra weight given to analysis and valuation.

Analyst's Opinion

• Score: 4.2 / 5
• Analyst Rating: Hold

Consensus Rating

Prothena has received a consensus rating of Hold. The company's average rating score is 2.33, and is based on 4 buy ratings, 4 hold ratings, and 1 sell rating.

Amount of Analyst Coverage

Prothena has been the subject of 8 research reports in the past 90 days, demonstrating strong analyst interest in this stock.

Earnings and Valuation

• Score: 1.3 / 5
• Proj. Earnings Growth: Growing

Earnings Growth

Earnings for Prothena are expected to grow in the coming year, from ($4.04) to ($3.33) per share.

Price to Earnings Ratio vs. the Market

The P/E ratio of Prothena is -3.16, 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 -3.16, which means that its earnings are negative and its P/E ratio cannot be compared to companies with positive earnings.

Price to Book Value per Share Ratio

Prothena has a P/B Ratio of 0.73. P/B Ratios below 1 indicate that a company could be undervalued with respect to its assets and liabilities.

Short Interest

• Score: 2.0 / 5
• Short Interest Level: Bearish

Percentage of Shares Shorted

11.01% 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 2.9, which is generally considered an acceptable ratio of short interest to trading volume.

Change versus previous month

Short interest in Prothena has recently increased by 5.67%, indicating that investor sentiment is decreasing significantly.

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.

Sustainability and ESG

• Score: N/A
• Environmental Score: N/A

Percentage of Shares Shorted

11.01% 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 2.9, which is generally considered an acceptable ratio of short interest to trading volume.

Change versus previous month

Short interest in Prothena has recently increased by 5.67%, indicating that investor sentiment is decreasing significantly.

News and Social Media

• Score: 1.0 / 5
• News Sentiment: N/A

News Sentiment

Prothena has a news sentiment score of -0.16. 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 lower news sentiment than the 0.56 average news sentiment score of Medical companies.

News Coverage This Week

MarketBeat has tracked 1 news article for Prothena this week, compared to 4 articles on an average week.

Search Interest

Only 1 people have searched for PRTA on MarketBeat in the last 30 days. This is a decrease of -75% compared to the previous 30 days.

Company Ownership

• Score: 1.7 / 5
• Insider Trading: N/A

Insider Buying vs. Insider Selling

In the past three months, Prothena insiders have not sold or bought any company stock.

Percentage Held by Insiders

Only 9.20% of the stock of Prothena is held by insiders.

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.

PRTA Stock Analysis - Frequently Asked Questions

How have PRTA shares performed this year?

Prothena's stock was trading at $13.85 at the beginning of 2025. Since then, PRTA stock has decreased by 52.5% and is now trading at $6.58.

How were Prothena's earnings last quarter?

Prothena Corporation plc (NASDAQ:PRTA) released its quarterly earnings data on Thursday, May, 8th. The biotechnology company reported ($1.12) earnings per share (EPS) for the quarter, missing the consensus estimate of ($0.92) by $0.20. The business's quarterly revenue was up 5500.0% compared to the same quarter last year.

How do I buy shares of Prothena?

Shares of PRTA stock can be purchased through any online brokerage account. Popular online brokerages with access to the U.S. stock market include Charles Schwab, E*TRADE, Fidelity, and Vanguard Brokerage Services.

What other stocks do shareholders of Prothena own?

Based on aggregate information from My MarketBeat watchlists, some other companies that Prothena investors own include Voyager Therapeutics (VYGR), American Water Works (AWK), Humana (HUM), Waste Connections (WCN), The RMR Group (RMR), DiamondRock Hospitality (DRH) and AU Optronics (AUOTY).

Company Calendar

• Last Earnings: 5/08/2025
• Today: 7/09/2025
• Next Earnings (Estimated): 8/06/2025
• Fiscal Year End: 12/31/2025

Industry, Sector and Symbol

• Stock Exchange: NASDAQ
• Sector: Medical
• Industry: MED - BIOMED/GENE
• Sub-Industry: Pharmaceutical Products
• Current Symbol: NASDAQ:PRTA
• CIK: 1559053
• Web: www.prothena.com
• Phone: (531) 236-2500
• Fax: 353-1902-3510
• Employees: 130
• Year Founded: N/A

Price Target and Rating

• Average Price Target for Prothena: $31.50
• High Price Target: $81.00
• Low Price Target: $6.00
• Potential Upside/Downside: +383.1%
• Consensus Rating: Hold
• Rating Score (0-4): 2.33
• Research Coverage: 9 Analysts

Profitability

• EPS (Trailing Twelve Months): ($2.08)
• Trailing P/E Ratio: N/A
• Forward P/E Ratio: N/A
• P/E Growth: N/A
• Net Income: -$122.31 million
• Net Margins: -79.94%
• Pretax Margin: -84.00%
• Return on Equity: -21.61%
• Return on Assets: -19.32%

Debt

• Debt-to-Equity Ratio: N/A
• Current Ratio: 9.00
• Quick Ratio: 9.00

Sales & Book Value

• Annual Sales: $135.16 million
• Price / Sales: 2.60
• Cash Flow: N/A
• Price / Cash Flow: N/A
• Book Value: $9.05 per share
• Price / Book: 0.72

Miscellaneous

• Outstanding Shares: 53,830,000
• Free Float: 48,875,000
• Market Cap: $350.97 million
• Optionable: Optionable
• Beta: 0.01