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PROTHENA CORP PUBLIC LTD CO General Counsel & Company Secretary Michael John Isaacs reported two transactions in ordinary shares. On July 29, 2026, he sold 8,386 shares in open-market or private trades at a weighted average of $8.4731 per share under a Rule 10b5-1 trading plan adopted on April 3, 2026. The trades were executed in multiple transactions at prices ranging from $8.40 to $8.65. On July 28, 2026, 4,694 shares were disposed of at $8.56 per share to satisfy exercise-price or tax-liability obligations by delivering or withholding shares. All transactions involved direct holdings.
BlackRock, Inc. reports beneficial ownership of common stock of Prothena Corporation plc on an amended Schedule 13G. BlackRock reports beneficial ownership of 3,587,480 shares of Prothena common stock, representing 6.9% of the outstanding class.
BlackRock has sole voting power over 3,533,090 shares and sole dispositive power over 3,587,480 shares, with no shared voting or dispositive power. Various underlying clients have rights to dividends or sale proceeds, but no single client holds more than five percent of Prothena’s outstanding common shares.
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.