OpenAI claws back business AI share as Anthropic's lead narrows

Anthropic's grip on enterprise AI spending is loosening. Ramp, the corporate card and spend-management firm whose AI Index tracks purchases at more than 70,000 US businesses, found Anthropic's share slipping from a high of 41% in May relative to OpenAI's 39% to a narrower 44%-to-40% split by July — with OpenAI's line moving up again.

The shift is being driven by price and product choice rather than any single deal. OpenAI's GPT-5.6 Sol is undercutting Anthropic's premium Fable 5 model on cost, and developers are voting with their spend. "GPT-5.6 Sol is really good, increasingly the choice for developers," said Ara Kharazian, an economist at Ramp.

The broader market is still expanding fast. The share of Ramp customers paying for AI tools crossed 50% in March 2026 and reached nearly 56% by July, meaning both companies are growing in absolute terms even as their relative positions shift.

On revenue, Anthropic remains well ahead in scale: it reported a $65 billion run rate in July against OpenAI's roughly $40 billion. But Ramp's usage data suggests that lead is not translating into proportional growth in business adoption, where the gap is closing.

The Ramp figures point to a market where enterprise buyers are increasingly price-sensitive once a model clears a quality bar. Fable 5's premium positioning has not converted into share gains proportional to Anthropic's revenue lead, which implies businesses are unwilling to pay much extra for incremental performance — a warning sign for any lab betting on premium pricing over volume.

OpenAI's gains, concentrated among developers choosing GPT-5.6 Sol, suggest the near-term battle for enterprise AI spend will be won on cost-per-task rather than headline capability. Anthropic's revenue scale gives it room to respond, but if Ramp's adoption trend continues, the next data points to watch are whether Anthropic cuts Fable 5 pricing or leans further into differentiated enterprise features to defend its lead. For the underlying data, the trend line matters more than the snapshot: OpenAI is climbing, and Anthropic's cushion is thinner than its revenue figures suggest.