PROTHENA (PRTA) General Counsel Michael Isaacs Sells 13,080 Shares

What Happened
Michael J. Isaacs, General Counsel & Company Secretary of Prothena Corp. (PRTA), disposed of a total of 13,080 shares in two transactions: 4,694 shares were surrendered to satisfy an exercise price or tax obligation on July 28, 2026 (reported value $40,181 at $8.56/share), and 8,386 shares were sold in an open‑market transaction on July 29, 2026 for about $71,055 (weighted average price $8.47). Combined proceeds were roughly $111,236. These were sales (not purchases), which are commonly routine transactions.

Key Details

• Dates and prices:
  • 2026-07-28: 4,694 shares disposed at $8.56 each for $40,181 (payment of exercise price/tax withholding).
  • 2026-07-29: 8,386 shares sold in the open market at a weighted average price of $8.47 each for $71,055; execution prices ranged $8.40–$8.65 per share.
• Shares owned after the transactions: Not disclosed in the provided filing.
• Footnotes: The open‑market sale(s) were effected pursuant to a Rule 10b5‑1 trading plan adopted April 3, 2026. The filer noted multiple trade prices and offered to provide the breakdown on request.
• Filing timeliness: No late‑filing indication provided in the supplied details.

Context

• The July 28 disposition (code F) reflects shares surrendered to cover an exercise price or tax liability — effectively a cashless/withholding disposition tied to an option exercise or similar event. The July 29 sale was executed under a prearranged 10b5‑1 plan, which allows insiders to sell according to a preset schedule to avoid trading‑timing concerns.
• Sales do not necessarily indicate negative insider sentiment; they can be routine (taxes, diversification, preplanned trading). For purchase activity, investors often view insider buys as a stronger signal.