Prothena (NASDAQ:PRTA) Major Shareholder William Scully Acquires 140,000 Shares of Company Stock

Prothena Corporation plc (NASDAQ:PRTA) major shareholder William Scully bought 140,000 shares of Prothena stock in a transaction dated Monday, November 9th. The stock was purchased at an average price of $8.53 per share, for a total transaction of $1,194,200.00. Following the purchase, the insider directly owned 977,000 shares in the company, valued at $8,333,810. This represents a 16.73% increase in their position. The purchase was disclosed in a filing with the SEC, which is accessible through this hyperlink. Major shareholders that own at least 10% of a company’s shares are required to disclose their transactions with the SEC.

Prothena Stock Performance

Shares of NASDAQ:PRTA opened at $8.56 on Wednesday. The company’s fifty day moving average is $8.62 and its 200-day moving average is $9.18. Prothena Corporation plc has a 52 week low of $7.73 and a 52 week high of $11.80. The company has a market capitalization of $439.56 million, a PE ratio of -17.83, a P/E/G ratio of 1.87 and a beta of -0.20.

Prothena (NASDAQ:PRTA) last announced its earnings results on Thursday, November 5th. The biotechnology company reported ($0.32) earnings per share (EPS) for the quarter, missing analysts’ consensus estimates of ($0.23) by ($0.09). Prothena had a negative return on equity of 9.98% and a negative net margin of 45.44%. The firm had revenue of $0.62 million for the quarter, compared to analyst estimates of $9.58 million. On average, analysts forecast that Prothena Corporation plc will post 0.13 EPS for the current year.

Prothena News Summary

Here are the key news stories impacting Prothena this week:

• Positive Sentiment: Major shareholder William P. Scully bought 140,000 shares for about $1.19 million, increasing his stake by 16.73% to 977,000 shares. The sizeable purchase may signal confidence in Prothena. SEC filing
• Positive Sentiment: HC Wainwright maintained its Buy rating and $30 price target, and raised its FY2026 EPS estimate to a loss of $0.44 from a loss of $0.47. Analyst estimates
• Neutral Sentiment: A Zacks article cited a consensus price target implying roughly 120% upside, while cautioning that price targets alone may be unreliable; the article pointed to earnings-estimate trends as a more relevant consideration. Zacks article
• Neutral Sentiment: A short-interest report described a large increase but listed short interest at zero shares and a 0.0-day ratio, making the data difficult to interpret. Short-interest report
• Negative Sentiment: HC Wainwright cut its EPS forecasts for FY2027–FY2029 and FY2030, and lowered its Q4 2026 estimate to a loss of $0.44 per share from a loss of $0.38. The revisions point to weaker expected earnings in several periods, despite the firm’s Buy rating. Analyst estimates

Institutional Inflows and Outflows

Several large investors have recently bought and sold shares of the company. Allspring Global Investments Holdings LLC acquired a new stake in shares of Prothena in the 3rd quarter valued at $239,000. Chicago Partners Investment Group LLC raised its position in shares of Prothena by 59.8% during the third quarter. Chicago Partners Investment Group LLC now owns 25,779 shares of the biotechnology company’s stock worth $211,000 after acquiring an additional 9,650 shares during the last quarter. Pinnacle Associates Ltd. lifted its stake in shares of Prothena by 6.2% during the third quarter. Pinnacle Associates Ltd. now owns 61,507 shares of the biotechnology company’s stock valued at $515,000 after acquiring an additional 3,589 shares during the period. Versant Capital Management Inc lifted its stake in shares of Prothena by 179.1% during the third quarter. Versant Capital Management Inc now owns 5,704 shares of the biotechnology company’s stock valued at $48,000 after acquiring an additional 3,660 shares during the period. Finally, Engineers Gate Manager LP acquired a new position in shares of Prothena during the second quarter valued at $404,000. Institutional investors and hedge funds own 97.08% of the company’s stock.

Analyst Upgrades and Downgrades

Several analysts have recently weighed in on the stock. UBS Group reaffirmed a “buy” rating on shares of Prothena in a report on Friday, July 24th. HC Wainwright reiterated a “buy” rating and issued a $30.00 target price on shares of Prothena in a research note on Friday, July 24th. Wall Street Zen downgraded Prothena from a “buy” rating to a “hold” rating in a report on Saturday, July 25th. Finally, Weiss Ratings downgraded Prothena from a “sell (d-)” rating to a “sell (e+)” rating in a report on Thursday, October 29th. One investment analyst has rated the stock with a Strong Buy rating, four have issued a Buy rating, one has issued a Hold rating and one has issued a Sell rating to the stock. According to data from MarketBeat, the company currently has an average rating of “Moderate Buy” and an average target price of $20.00.

Prothena Company Profile

Prothena Corporation plc (NASDAQ: PRTA) is a clinical-stage biotechnology company focused on discovering and developing novel medicines for serious neurodegenerative and rare peripheral diseases. Its research is centered on disease-causing proteins, including amyloid-beta, alpha-synuclein and transthyretin, with the goal of creating antibody-based therapies that address underlying disease mechanisms. The company’s product pipeline has included birtamimab, an investigational antibody being developed for the treatment of AL amyloidosis, and prasinezumab, an investigational alpha-synuclein antibody being developed in collaboration with Roche for certain forms of Parkinson’s disease.