As Chinese AI companies armed with cost-effective open-weight models accelerate their chase of OpenAI and Anthropic, the race for AI leadership between OpenAI and Anthropic is also heating up.

OpenAI has recently sharply raised its share in the enterprise market, where it had trailed Anthropic. A survey result also showed the two companies are neck and neck in the enterprise market.

A startup called OpenRouter, which supports access to various AI models, analysed spending data from about 120,000 companies using Anthropic and OpenAI AI tools. The results showed the two companies’ shares looked similar in September.

OpenAI’s strong showing stands out given that Anthropic accounted for 75 percent of total spending early this year.

Analysts said OpenAI’s launch in June of the GPT-5.6 model series (Sol, Terra and Luna), focused on value for money, helped reverse the mood.

OpenAI cut prices as soon as it released the GPT-5.6 series, lowering Luna by 80 percent and Terra by up to 20 percent. It also released additional follow-up versions of models with improved price-to-performance. Peter Walker, head of insights at OpenRouter, said, "GPT-5.6 opened up a new market segment for OpenAI that does not exist in Anthropic’s model lineup."

OpenRouter’s data mainly reflected spending by startups that deploy AI as a core business foundation, some tech companies with relatively long operating histories, and large corporations.

Data from fintech startup Ramp is also notable for OpenAI.

Ara Karajian (아라 카라지안), an economist at Ramp, said an analysis of data from about 70,000 of its customers in mid-September showed spending on OpenAI models surpassed Anthropic for the first time. It was the first time since last December. Anthropic later regained the lead by a narrow margin, but it was another sign that OpenAI is gaining weight in the enterprise market, where it had been relatively weak. Ramp’s data includes some Fortune 500 companies in addition to high-growth tech firms of various sizes. Spending by individual developers was excluded from the analysis.

David Joo (데이비드 주), co-founder and CEO of AI sales platform startup Reevo, told WSJ, "We are switching AI models from Anthropic to OpenAI to cut costs and reduce dependence on a specific model developer." He said, "The days of relying on only one model developer are over," adding, "The preferred model could change again. Things are changing too fast."

WSJ reported that Anthropic’s launch of its high-performance AI model Fable5, along with its announcement that it would retain user data for 30 days for trust and safety purposes, also influenced companies to move to OpenAI.

OpenAI has strengthened its presence in the enterprise market with the GPT-5.6 series, but the situation could change as Anthropic responds. Anthropic unveiled the Claude 5.5 model lineup in late September, emphasising price-to-performance.