Anthropic captures 73% of new enterprise AI buyers as it closes in on OpenAI's revenue

Anthropic is winning 73% of first-time enterprise AI purchases, according to Ramp's March 2026 AI Index tracking 50,000+ businesses. Anthropic's adoption grew 4.9% month-over-month while OpenAI posted its first monthly decline at -1.5%. Nearly one in four businesses on Ramp now pays for Anthropic, up from one in 25 a year ago.

At 10x annual growth versus OpenAI's 3.4x, the revenue crossover is a matter of when, not if. The shift is not purely about benchmarks — Claude Code and OpenAI's Codex are comparable on performance, and Codex is cheaper. Yet Anthropic is actively turning away revenue because it cannot meet compute demand. The data suggests enterprise buyers are making a values-based choice alongside a product choice. For builders deciding which platform to standardize on, this is the clearest signal yet that Anthropic's enterprise position is structurally stronger than OpenAI's.