Prothena (NASDAQ:PRTA) Major Shareholder William Scully Acquires 27,000 Shares of Stock

Posted by Brenda Bartman on Sep 3rd, 2026

Prothena Corporation plc (NASDAQ:PRTA – Get Free Report) major shareholder William Scully acquired 27,000 shares of the company’s stock in a transaction dated Wednesday, September 2nd. The stock was acquired at an average price of $9.47 per share, with a total value of $255,690.00. Following the purchase, the insider owned 827,000 shares in the company, valued at approximately $7,831,690. This represents a 3.38% increase in their position. The transaction was disclosed in a document filed with the Securities & Exchange Commission, which is accessible through the SEC website. Major shareholders that own 10% or more of a company’s shares are required to disclose their transactions with the SEC.

Prothena Trading Down 0.9%

NASDAQ:PRTA traded down $0.09 during mid-day trading on Thursday, hitting $9.60. The company’s stock had a trading volume of 275,198 shares, compared to its average volume of 508,436. The company has a market capitalization of $502.59 million, a price-to-earnings ratio of -11.43, a P/E/G ratio of 3.39 and a beta of -0.33. Prothena Corporation plc has a fifty-two week low of $7.73 and a fifty-two week high of $11.80. The stock has a fifty day moving average of $9.06 and a 200-day moving average of $9.41.

Prothena (NASDAQ:PRTA – Get Free Report) last posted its earnings results on Thursday, August 6th. The biotechnology company reported ($0.32) EPS for the quarter, topping the consensus estimate of ($0.39) by $0.07. The business had revenue of $1.01 million during the quarter, compared to the consensus estimate of $0.42 million. Prothena had a negative return on equity of 16.45% and a negative net margin of 80.68%. On average, equities analysts anticipate that Prothena Corporation plc will post 0.08 earnings per share for the current fiscal year.

Wall Street Analysts Forecast Growth

PRTA has been the subject of several recent analyst reports. HC Wainwright reaffirmed a “buy” rating and set a $30.00 price objective on shares of Prothena in a report on Friday, July 24th. Citizens Jmp boosted their target price on Prothena from $19.00 to $20.00 and gave the stock a “market outperform” rating in a report on Friday, May 8th. Wall Street Zen lowered Prothena from a “buy” rating to a “hold” rating in a research report on Saturday, July 25th. Citigroup reaffirmed an “outperform” rating on shares of Prothena in a report on Friday, May 8th. Finally, Weiss Ratings downgraded Prothena from a “sell (d-)” rating to a “sell (e+)” rating in a research report on Tuesday, August 11th. One analyst has rated the stock with a Strong Buy rating, five have assigned a Buy rating, one has given a Hold rating and one has given a Sell rating to the company. Based on data from MarketBeat, Prothena currently has an average rating of “Moderate Buy” and a consensus target price of $24.57.

View Our Latest Research Report on Prothena

Hedge Funds Weigh In On Prothena

A number of institutional investors have recently modified their holdings of the stock. California State Teachers Retirement System grew its holdings in Prothena by 151.8% during the 2nd quarter. California State Teachers Retirement System now owns 6,001 shares of the biotechnology company’s stock worth $613,000 after acquiring an additional 3,618 shares during the period. Headlands Technologies LLC bought a new position in shares of Prothena in the 2nd quarter worth $148,000. Public Employees Retirement System of Ohio acquired a new stake in shares of Prothena during the second quarter worth $413,000. Great Lakes Advisors LLC bought a new stake in Prothena in the second quarter valued at about $281,000. Finally, Hennion & Walsh Asset Management Inc. increased its holdings in Prothena by 2.5% in the second quarter. Hennion & Walsh Asset Management Inc. now owns 90,795 shares of the biotechnology company’s stock valued at $889,000 after purchasing an additional 2,251 shares during the last quarter. 97.08% of the stock is owned by institutional investors.

Prothena Company Profile

(Get Free Report)

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.