According to the latest data from OpenRouter, among approximately 120,000 enterprises using both Anthropic and OpenAI products, the expenditure share between the two companies was roughly equal in September, a significant shift from early this year when Anthropic accounted for three-quarters of the spending. This reversal is primarily attributed to OpenAI's GPT-5.6 series models, launched this summer, which focused on cost efficiency and featured substantial price reductions, including an 80% cut for GPT-5.6 Luna and a 20% cut for Terra. Concurrently, Anthropic's flagship model Fable 5's data retention policy also led to the loss of some enterprise clients. Both companies face capital expenditure pressure and are preparing for IPOs: Anthropic could go public as early as November this year, with OpenAI expected to follow next year. Wall Street is closely scrutinizing whether they can sustain valuations exceeding one trillion dollars. Anthropic released its new generation Claude 5.5 series models in late September, emphasizing lower costs and higher efficiency to counter competition.