Welcome to our dedicated page for Prothena SEC filings (Ticker: PRTA), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Prothena Corporation plc filings document regulatory disclosures for an Irish clinical-stage biotechnology issuer with ordinary shares listed on Nasdaq. Recent 8-K reports furnish quarterly and annual financial results, business highlights, collaboration-related revenue, capital actions such as share repurchase authorization, and board or officer changes.
Proxy materials describe shareholder voting matters, executive compensation and board governance. The company’s filings also record ordinary-share capital matters, including shareholder approval of a capital reduction to create distributable reserves, along with exhibit-based press releases and Inline XBRL cover data.
PROTHENA CORP PUBLIC LTD CO large shareholder William P. Scully reported an open-market purchase of 20,000 ordinary shares of PRTA. The transaction occurred on June 16, 2026 at a weighted average price of $7.8995 per share, with individual trades between $7.8600 and $7.9312.
After this purchase, Scully directly holds 756,000 ordinary shares. The filing also shows indirect holdings of 52,000 shares held by his spouse and 80,000 shares held by Manatee Equity Fund LLC, for which he disclaims beneficial ownership except to the extent of his pecuniary interest.
PROTHENA CORP PUBLIC LTD CO ten percent owner William P. Scully reported a bona fide gift of 325,000 ordinary shares on June 15, 2026. The gift was recorded at a price of $0.00 per share.
After this transfer, Scully directly holds 736,000 ordinary shares and has additional indirect holdings of 52,000 shares through his spouse and 80,000 shares through Manatee Equity Fund LLC. He disclaims beneficial ownership of certain indirectly held securities except to the extent of his pecuniary interest.
Prothena Corp Public Ltd Co insider William P. Scully, a ten percent owner, bought 125,000 ordinary shares in an open-market purchase at a weighted average price of $8.1698 per share. The trade on June 11, 2026 increased his direct holdings to 1,061,000 ordinary shares.
The filing notes the shares were purchased in multiple transactions at prices ranging from $7.84 to $8.43 per share. It also reports additional indirect holdings of 52,000 shares held by his spouse and 80,000 shares held by Manatee Equity Fund LLC. Scully disclaims beneficial ownership of certain reported securities except to the extent of his pecuniary interest in them.
Prothena Corp Public Ltd Co General Counsel & Company Secretary Michael John Isaacs has reported his initial holdings. He directly owns 48,825 ordinary shares. He also holds several stock options over ordinary shares at exercise prices ranging from $10.99 to $52.97, with expiration dates between 2030 and 2036.
Certain options are already fully vested, while others vest 25% on specific dates and then in equal monthly installments, in each case subject to his continued employment with the company.
PROTHENA CORP PUBLIC LTD CO major shareholder William P. Scully reported an open-market purchase of 50,000 ordinary shares on June 4, 2026 at a weighted average price of $9.3059 per share. Following this transaction, he holds 936,000 shares directly.
He also reports indirect holdings of 52,000 shares by his spouse and 80,000 shares by Manatee Equity Fund LLC, and disclaims beneficial ownership of these indirect positions except to the extent of his pecuniary interest.
PROTHENA CORP PUBLIC LTD CO major shareholder William P. Scully reported an open-market purchase of 50,000 ordinary shares at a weighted average price of $9.426 per share on June 2, 2026. Following this transaction, he directly holds 886,000 ordinary shares.
The filing also lists indirect holdings of 52,000 shares held by his spouse and 80,000 shares held by Manatee Equity Fund LLC. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest in them.
PROTHENA CORP PUBLIC LTD CO major shareholder William P. Scully reported an open-market purchase of 100,000 ordinary shares of PRTA at a weighted average price of $9.813 per share. After this transaction, he directly held 836,000 ordinary shares.
The filing also lists indirect holdings of 52,000 shares held by his spouse and 80,000 shares held by Manatee Equity Fund LLC. A footnote states that he disclaims beneficial ownership of certain securities except to the extent of his pecuniary interest.
Prothena Corp Public Ltd Co director Daniel G. Welch received a grant of stock options on Ordinary Shares covering 27,000 shares at an exercise price of $9.76 per share. These options vest 100% on the earlier of the first anniversary of the May 15, 2026 grant date or the company’s 2027 annual general meeting, assuming he continues to serve as a director through that date. Following this grant, his reported derivative holdings in this option series total 27,000 shares, and the filing shows no related sales or exercises.
PROTHENA CORP PUBLIC LTD CO director Dennis J. Selkoe received a grant of stock options for 27,000 shares. These options give the right to buy ordinary shares at an exercise price of $9.76 per share and are held as a direct ownership position.
The options will vest and become exercisable in full on the earlier of the first anniversary of the May 15, 2026 grant date or the day of the company’s 2027 annual general meeting, assuming he continues serving as a director through that date. After this grant, he holds options covering 27,000 shares.