This market intelligence report profiles 25 AI agent companies collectively valued at $100B+ with $4B+ in combined ARR, spanning six verticals: Coding (Cursor $29.3B, Cognition $10.2B, Replit $3B), Customer Service (Sierra $10B, Decagon $1.5B), Legal AI (Harvey $8B, EvenUp $1B), Healthcare (Hippocratic $3.5B, Abridge $850M), Sales/Recruiting (Mercor $10B, 11x $350M), and Enterprise (Glean $7.2B, Cohere $5.5B). Key trends include unprecedented speed-to-scale (Cursor hit $1B ARR faster than any SaaS ever), extreme valuation multiples (20-100x revenue), outcome-based pricing innovation (Sierra's per-resolution model, Hippocratic's $9/hr agents), and dominance by young technical founders with deep domain expertise.