Vertical AI Agents Eat Horizontal SaaS: Harvey, Ambience, and Procore Carve Up a ~$450B Vertical Market

Rob Saker (Medium)·medium signal

Analysts now project 30-40% of the ~$450B vertical SaaS market will be reshaped by AI agents through 2028. Legal (Harvey, serving A&O Shearman, PwC Legal, Macfarlanes), healthcare (Ambience generating real-time clinical notes, with ~$150B/yr in projected U.S. savings), and construction (Procore's Datagrid-acquisition AI generating bids and change orders) show domain-specific agents winning on data + workflow moats. Vertical SaaS sold at a 41% premium to horizontal SaaS in 2025 — the largest gap on record — and that premium is now what vertical AI is targeting.