Models
Model APIs: Anthropic overtook OpenAI in two years
Between 2023 and 2025, Anthropic went from 12% to 40% of enterprise API spend, OpenAI from 50% to 27%. Open source is shrinking.
The model market re-concentrated much faster than expected. According to Menlo Ventures, Anthropic accounted for 12% of enterprise LLM API spend in 2023 and 40% in 2025. Over the same period, OpenAI fell from 50% to 27%.
Open source against the tide
Contrary to the idea that falling prices would favour open models, their share fell from 19% to 11%. Chinese open-source models account for just 1% of enterprise API usage.
A supply risk
The top three vendors hold 88% of API spend. A product built on a single model inherits that vendor's outages, pricing and legal exposure.
Source: Menlo Ventures, The State of Generative AI in the Enterprise, 2025.