Director William P. Scully filed a Form 4 with the SEC on September 3, 2026, disclosing the open-market purchase of 27,000 ordinary shares of Prothena Corp Public Ltd Co (NASDAQ:PRTA) on September 2, 2026.

Key Highlights

  • Shares purchased: 27,000 ordinary shares, par value $0.01 per share, acquired on September 2, 2026.
  • Weighted average price: $9.4718 per share, with individual transaction prices ranging from $9.4072 to $9.6100, inclusive.
  • Direct holdings after transaction: 827,000 ordinary shares held directly following the reported purchase.
  • Indirect holdings: An additional 83,500 shares held indirectly through Manatee Equity Fund LLC, and 52,000 shares held indirectly by spouse.
  • Beneficial ownership disclaimer: Scully disclaims beneficial ownership of the shares held through Manatee Equity Fund LLC except to the extent of his pecuniary interest therein.

Scully's Open-Market Purchase and Resulting Ownership in Prothena

According to the filing, William P. Scully, identified as a director of Prothena Corp Public Ltd Co (NASDAQ:PRTA), acquired 27,000 ordinary shares on September 2, 2026, through an open-market purchase coded "P" in the filing. The reported price of $9.4718 is described as a weighted average, as the shares were purchased across multiple transactions at prices ranging from $9.4072 to $9.6100 per share. The filing notes that Scully has undertaken to provide full detail on the number of shares purchased at each separate price upon request by the company, any security holder, or SEC staff.

Following the reported transaction, the filing discloses that Scully directly owns 827,000 ordinary shares. In addition to his direct holdings, the filing reports 83,500 shares held indirectly through Manatee Equity Fund LLC, and 52,000 shares held indirectly by his spouse. Scully disclaims beneficial ownership of the shares attributed to Manatee Equity Fund LLC, except to the extent of his pecuniary interest in that entity, as stated in the filing's footnotes.

No derivative securities transactions were reported in Table II of the filing. The Form 4 was signed by Reid E. Buchanan by power of attorney from William P. Scully and filed on September 3, 2026.

What Was Disclosed

Director William P. Scully reported the purchase of 27,000 ordinary shares of Prothena Corp Public Ltd Co at a weighted average price of $9.4718, bringing his direct beneficial ownership to 827,000 shares, with additional indirect holdings of 135,500 shares.