Vertical SaaS AI: $450B Market With 30-40% Expected to Be Reshaped by AI Agents by 2028

Menlo Ventures·medium signal

Vertical SaaS AI agents represent the most defensible startup opportunity, with the global vertical SaaS market at roughly $450B and 30-40% expected to be reshaped by AI agents between 2026-2028. Vertical AI companies grow 3x faster than horizontal competitors, charge 2-4x more per seat, and retain customers at dramatically higher rates. Key players include Harvey (legal), Hippocratic AI (healthcare), and EvenUp (personal injury law) — industries where domain-specific regulation creates natural moats against horizontal AI tools.