Anthropic has pulled off one of the fastest enterprise adoption reversals in AI history, according to Ramp's March 2026 AI Index — a spending dataset drawn from tens of thousands of businesses.

By the Numbers

Overall business AI adoption hit a record 47.6% in February. Within that, Anthropic's share grew 4.9 percentage points month over month — its largest monthly gain since Ramp began tracking. OpenAI, meanwhile, shed 1.5 points, the steepest single-month decline any AI company has recorded on the index.

The gap is still wide: OpenAI holds roughly 34.4% of business AI subscriptions versus Anthropic's 24.4%. But the trajectory has flipped. "Nearly one in four businesses on Ramp now pays for Anthropic," wrote Ramp economist Ara Kharazian. "A year ago, it was one in 25."

First-Time Buyers Break Toward Anthropic

The stat that caught the most attention: among businesses purchasing AI services for the first time, Anthropic now wins about 70% of head-to-head matchups against OpenAI. That's a full reversal from the trend lines of 2025, when OpenAI accelerated faster than any competitor.

Why the Shift?

Kharazian points to Anthropic's early-adopter base — engineers, AI evangelists, the "AI guy" on the team — now carrying the product into the mainstream. Observers also note timing: Anthropic's public refusal in late February to strip safety guardrails for Pentagon use cases positioned it as the responsible choice for enterprise buyers wary of liability.

OpenAI, watching the numbers, is reportedly refocusing strategy on business and developer sales — the exact markets where Anthropic is now winning.