Prothena (NASDAQ:PRTA) Stock: Insider William Scully Acquires 140,000 Shares

Prothena Corporation plc (NASDAQ:PRTA) major shareholder William Scully acquired 140,000 shares of Prothena stock in a transaction dated Monday, November 9th. The shares were purchased at an average price of $8.53 per share, with a total value of $1,194,200.00. Following the acquisition, the insider owned 977,000 shares of the company’s stock, valued at approximately $8,333,810. This trade represents a 16.73% increase in their ownership of the stock. The transaction was disclosed in a legal filing with the SEC, which is available at this link. Large shareholders that own at least 10% of a company’s stock are required to disclose their sales and purchases with the SEC.

Prothena Price Performance

NASDAQ PRTA traded down $0.22 on Tuesday, reaching $8.55. The stock had a trading volume of 231,682 shares, compared to its average volume of 508,785. The firm has a fifty day moving average of $8.64 and a two-hundred day moving average of $9.19. Prothena Corporation plc has a 1-year low of $7.73 and a 1-year high of $11.80. The company has a market cap of $447.59 million, a P/E ratio of -17.81, a price-to-earnings-growth ratio of 2.96 and a beta of -0.20.

Prothena (NASDAQ:PRTA) last posted its earnings results on Thursday, November 5th. The biotechnology company reported ($0.32) earnings per share for the quarter, missing analysts’ consensus estimates of ($0.23) by ($0.09). Prothena had a negative return on equity of 16.45% and a negative net margin of 80.68%. The firm had revenue of $0.62 million for the quarter, compared to analyst estimates of $9.58 million. Research analysts predict that Prothena Corporation plc will post 0.08 EPS for the current fiscal year.

Prothena News Summary

Here are the key news stories impacting Prothena this week:

• Positive Sentiment: A Zacks report says the consensus price target implies about 120% upside for PRTA. It cautions that price targets alone are not especially reliable, while upward earnings-estimate revisions could be a more constructive near-term signal. Wall Street Analysts See a 120.16% Upside in Prothena (PRTA): Can the Stock Really Move This High?
• Positive Sentiment: HC Wainwright maintained its Buy rating and $30 price target, a bullish view on the shares. Prothena analyst estimates and rating
• Negative Sentiment: HC Wainwright lowered its estimates for FY2027–FY2029 and FY2030, and increased its projected Q4 2026 loss to $0.44 per share from $0.38. These cuts point to weaker expected earnings in several future periods and temper the bullish target. It modestly raised its FY2026 estimate, however, to a loss of $0.44 per share from $0.47. Prothena analyst earnings estimates

Institutional Investors Weigh In On Prothena

Hedge funds have recently made changes to their positions in the stock. Rubric Capital Management LP raised its position in Prothena by 36.0% in the first quarter. Rubric Capital Management LP now owns 5,000,000 shares of the biotechnology company’s stock valued at $48,600,000 after purchasing an additional 1,322,669 shares during the period. Renaissance Technologies LLC lifted its stake in shares of Prothena by 39.5% during the first quarter. Renaissance Technologies LLC now owns 607,515 shares of the biotechnology company’s stock worth $5,905,000 after purchasing an additional 172,000 shares in the last quarter. ADAR1 Capital Management LLC boosted its position in shares of Prothena by 8.5% in the first quarter. ADAR1 Capital Management LLC now owns 1,581,443 shares of the biotechnology company’s stock worth $15,372,000 after buying an additional 123,679 shares during the period. Public Employees Retirement System of Ohio purchased a new stake in shares of Prothena in the second quarter worth about $413,000. Finally, Engineers Gate Manager LP purchased a new stake in shares of Prothena in the second quarter worth about $404,000. 97.08% of the stock is currently owned by institutional investors and hedge funds.

Wall Street Analysts Forecast Growth

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

About Prothena

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.