SCHEDULE: Scully Boosts Prothena Stake to 9.9% in New Filing

William P. Scully has disclosed an increased beneficial ownership of 9.9% in Prothena Corp Public Ltd Co, totaling 5,351,846 Ordinary Shares.

Summary

• William P. Scully reported beneficial ownership of 5,351,846 Ordinary Shares of Prothena Corp Public Ltd Co.
• This ownership represents approximately 9.9% of the company's outstanding Ordinary Shares.
• The shares outstanding for Prothena Corp Public Ltd Co were 53,826,982 as of July 25, 2025, according to the company's most recent Form 10-Q.
• Scully holds sole voting and dispositive power over 768,000 shares.
• Scully holds shared voting and dispositive power over 4,583,846 shares.
• The beneficial ownership includes shares held directly, through Manatee Equity Fund LLC, various IRAs, a spouse's IRA, a spouse, and several trusts where Scully has sole or shared control/dispositive power.

Sentiment

Score: 5

Explanation: The filing is a factual disclosure of beneficial ownership and does not contain information that would inherently convey positive or negative sentiment regarding the company's performance or prospects. The large stake by an individual investor could be interpreted as a positive signal by some, but the filing itself is neutral.

Future Outlook

NA

Industry Context

This filing is a standard disclosure of a significant ownership stake by an individual investor in a publicly traded company. It does not provide specific industry context beyond the company's identity.

Stakeholder Impact

• Shareholders: Disclosure of a significant individual stake provides transparency regarding the ownership structure and potential influence of a large investor.

Key Dates

Keywords

Prothena Corp, William P. Scully, Beneficial Ownership, SEC Filing, Schedule 13G, Ordinary Shares, Institutional Investor, Shareholder Stake