OpenAI surpasses Anthropic after two and a half years, Astra has the highest spending share

OpenRouter's latest data shows that last week, user spending on OpenAI models surpassed that of Anthropic. This is the first time since February 2024 that Anthropic's two-and-a-half-year lead has been broken. The biggest change came from Astra, whose model accounted for about 19% of the total spending on OpenAI and Anthropic, surpassing Opus 5's 16%, making it the highest-spending model last week, while GPT-5.6 Sol and Luna each accounted for about 10%.

OpenAI's rebound had actually begun earlier. After significant price reductions for Terra and Luna this summer, usage on OpenRouter surged, with some users continuing to use it even after the discounts ended. After Astra launched, OpenAI ultimately pushed its spending share above 50%. However, this only represents the relative spending of OpenAI and Anthropic on OpenRouter and cannot be directly equated to the entire API market or the total revenue of the two companies.