A statement of changes in beneficial ownership filed on September 21, 2026, disclosed that William P. Scully, a director of Prothena Corp Public Ltd Co (NASDAQ:PRTA), purchased 100,000 ordinary shares on September 18, 2026.

Key Highlights

  • Purchase transaction: William P. Scully acquired 100,000 ordinary shares (par value $0.01 per share) on September 18, 2026, with a weighted average price of $8.4346 per share.
  • Price range: The shares were purchased in multiple transactions at prices ranging from $8.3350 to $8.4829, inclusive, according to the filing.
  • Direct ownership after transaction: Scully directly holds 927,000 ordinary shares following the reported purchase.
  • Indirect holdings: An additional 83,500 shares are held indirectly by Manatee Equity Fund LLC, and 52,000 shares are held indirectly by his spouse.
  • Disclaimer of beneficial ownership: Scully disclaims beneficial ownership of the shares held by Manatee Equity Fund LLC except to the extent of his pecuniary interest therein.

Director Share Purchase at Prothena Corp Public Ltd Co

According to the filing, William P. Scully, identified as a director of Prothena Corp Public Ltd Co, executed a purchase (transaction code "P") of 100,000 ordinary shares of the company on September 18, 2026. The filing reports a weighted average price of $8.4346 per share, and notes that the shares were acquired across multiple transactions at prices ranging from $8.3350 to $8.4829, inclusive. The filing further states that Scully undertakes to provide full information on the number of shares purchased at each separate price within that range upon request to the company, any security holder, or the staff of the Securities and Exchange Commission.

Prothena Corp Public Ltd Co is incorporated as a public limited company, as reflected in its registered name in the filing. Following the September 18, 2026 purchase, the filing reports that Scully directly beneficially owns 927,000 ordinary shares. Beyond his direct holdings, the filing discloses 83,500 shares held indirectly through Manatee Equity Fund LLC and 52,000 shares held indirectly by his spouse. Scully's address is listed in the filing as 771 Manatee Cove, Vero Beach, Florida 32963. No derivative securities transactions were reported in Table II of the filing. The filing was signed by Reid E. Buchanan by power of attorney from William P. Scully and was dated September 21, 2026.

What Was Disclosed

The filing disclosed a direct purchase of 100,000 ordinary shares of NASDAQ:PRTA by director William P. Scully on September 18, 2026, at a weighted average price of $8.4346 per share, bringing his direct beneficial ownership to 927,000 shares.