Director William P. Scully filed a Form 4 with the SEC on October 26, 2026, disclosing two open-market purchases of Prothena Corp Public Ltd Co (NASDAQ:PRTA) ordinary shares on October 22 and October 23, 2026.

Key Highlights

  • October 22 purchase: Scully acquired 100,000 ordinary shares at a weighted average price of $8.1852, with individual transaction prices ranging from $8.0600 to $8.2800.
  • October 23 purchase: Scully acquired an additional 50,000 ordinary shares at a weighted average price of $8.0705, with individual transaction prices ranging from $7.9884 to $8.1500.
  • Direct ownership following transactions: Scully directly holds 1,187,000 ordinary shares after the reported purchases.
  • Indirect holdings: An additional 529,000 shares are held indirectly by spouse, and 187,000 shares are held indirectly by Manatee Equity Fund LLC.
  • Disclaimer: According to the filing, Scully "disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein" with respect to the Manatee Equity Fund LLC shares.
  • Relationship to issuer: Scully is identified in the filing as a Director of Prothena Corp Public Ltd Co.

Scully's Two-Day Purchase of 150,000 Prothena Ordinary Shares

According to the Form 4 filed on October 26, 2026, William P. Scully, a director of Prothena Corp Public Ltd Co, purchased ordinary shares of the company across two consecutive trading days. On October 22, 2026, Scully acquired 100,000 ordinary shares (par value $0.01 per share) at a weighted average price of $8.1852. The filing notes that these shares were purchased in multiple transactions at prices ranging from $8.0600 to $8.2800, inclusive.

On October 23, 2026, Scully acquired an additional 50,000 ordinary shares at a weighted average price of $8.0705, with individual transaction prices ranging from $7.9884 to $8.1500, inclusive. Both transactions are coded as open-market purchases. Following these two transactions, the filing reports that Scully directly holds 1,187,000 ordinary shares. The filing also discloses 529,000 shares held indirectly by spouse and 187,000 shares held indirectly by Manatee Equity Fund LLC, for which Scully disclaims beneficial ownership except to the extent of his pecuniary interest.

The filing was signed by Reid E. Buchanan by power of attorney from William P. Scully, and dated October 26, 2026. The filing notes that upon request, Scully undertakes to provide full information regarding the number of shares purchased at each separate price within the stated ranges to Prothena Corp Public Ltd Co, any security holder, or the SEC staff.

What Was Disclosed

Director William P. Scully reported the purchase of 150,000 Prothena ordinary shares across two transactions on October 22 and October 23, 2026, at weighted average prices of $8.1852 and $8.0705, respectively, bringing his direct ownership to 1,187,000 shares.