Muse from Meta has dominated the top free spot on the U.S. App Store since mid-September 2026 after launching September 8 as an agentic AI tool that connects to user accounts for tasks like email, shopping, and scheduling. Heavy Meta promotion, rapid platform expansions to Mac and iPad with new integrations such as Asana, Canva, and QuickBooks, plus millions of downloads have reinforced its position ahead of competitors like ChatGPT. Traders assign it a 98.1% implied probability for October 16 because no other app shows comparable momentum or visibility. A sudden competitor release, major service outage, or policy change could theoretically shift rankings overnight, though historical patterns and current install trends make such reversals unlikely in a single day.