Prothena (NASDAQ:PRTA) Major Shareholder William Scully Acquires 50,000 Shares of Stock

Posted by Brian Himes on Jun 6th, 2026

Prothena Corporation plc (NASDAQ:PRTA – Get Free Report) major shareholder William Scully purchased 50,000 shares of Prothena stock in a transaction on Thursday, June 4th. The stock was bought at an average price of $9.31 per share, for a total transaction of $465,500.00. Following the transaction, the insider directly owned 936,000 shares in the company, valued at approximately $8,714,160. The trade was a 5.64% increase in their position. The purchase was disclosed in a filing with the SEC, which can be accessed through this hyperlink. Major shareholders that own at least 10% of a company’s stock are required to disclose their transactions with the SEC.

Prothena Price Performance

Shares of NASDAQ:PRTA opened at $8.79 on Friday. Prothena Corporation plc has a 1 year low of $4.95 and a 1 year high of $11.80. The business’s 50-day moving average is $10.12 and its 200-day moving average is $9.71. The company has a market capitalization of $460.16 million, a price-to-earnings ratio of -3.12, a P/E/G ratio of 1.48 and a beta of -0.25.

Prothena (NASDAQ:PRTA – Get Free Report) last announced its earnings results on Thursday, May 7th. The biotechnology company reported $0.60 EPS for the quarter, beating the consensus estimate of ($0.31) by $0.91. Prothena had a negative return on equity of 43.44% and a negative net margin of 260.92%.The company had revenue of $51.08 million for the quarter, compared to analyst estimates of $0.81 million. Analysts anticipate that Prothena Corporation plc will post 0.18 EPS for the current year.

Institutional Inflows and Outflows

Institutional investors have recently added to or reduced their stakes in the company. JPMorgan Chase & Co. raised its stake in Prothena by 479.6% during the 3rd quarter. JPMorgan Chase & Co. now owns 735,765 shares of the biotechnology company’s stock worth $7,181,000 after buying an additional 608,814 shares during the period. Focused Wealth Management Inc raised its stake in Prothena by 88.1% during the 4th quarter. Focused Wealth Management Inc now owns 107,479 shares of the biotechnology company’s stock worth $1,026,000 after buying an additional 50,350 shares during the period. SG Americas Securities LLC raised its stake in Prothena by 11.1% during the 4th quarter. SG Americas Securities LLC now owns 63,018 shares of the biotechnology company’s stock worth $602,000 after buying an additional 6,299 shares during the period. Hennion & Walsh Asset Management Inc. raised its stake in Prothena by 7.9% during the 4th quarter. Hennion & Walsh Asset Management Inc. now owns 91,284 shares of the biotechnology company’s stock worth $872,000 after buying an additional 6,686 shares during the period. Finally, Penbrook Management LLC acquired a new position in Prothena during the 1st quarter worth approximately $2,641,000. 97.08% of the stock is owned by institutional investors and hedge funds.

Wall Street Analysts Forecast Growth

Several equities research analysts recently commented on PRTA shares. Weiss Ratings lowered Prothena from a “sell (d-)” rating to a “sell (e+)” rating in a research report on Tuesday. Wall Street Zen upgraded Prothena from a “hold” rating to a “buy” rating in a research report on Saturday. Stifel Nicolaus set a $19.00 target price on Prothena in a research report on Friday, March 13th. Citizens Jmp upped their target price on Prothena from $19.00 to $20.00 and gave the company a “market outperform” rating in a research report on Friday, May 8th. Finally, Royal Bank Of Canada upped their target price on Prothena from $11.00 to $12.00 and gave the company a “sector perform” rating in a research report on Friday, February 20th. One research analyst has rated the stock with a Strong Buy rating, four have assigned a Buy rating, two have assigned a Hold rating and one has assigned a Sell rating to the company. According to MarketBeat, the company currently has an average rating of “Moderate Buy” and a consensus target price of $23.75.

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About Prothena

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Prothena Corporation plc is a clinical-stage biotechnology company dedicated to the discovery and development of novel therapies for neurodegenerative and rare diseases driven by misfolded proteins. The company’s research focuses on immunotherapies and small molecules designed to target and clear disease-causing protein aggregates. Prothena leverages proprietary protein engineering and antibody discovery platforms to advance candidates through preclinical and clinical stages.

The company’s most advanced program is an antibody targeting aggregated alpha-synuclein for the potential treatment of Parkinson’s disease, currently in mid-stage clinical trials.