This page focuses specifically on calendar year 2025 — the period from January 2025 through December 2025. Statistics are drawn from publicly available studies, primary company announcements, and contemporaneous research reports. Menlo Ventures' "State of Generative AI in the Enterprise" reports (mid-year and year-end) are the most authoritative source on enterprise LLM market share dynamics in 2025 and are cited as the primary source for vendor share statistics.
Note that Menlo Ventures' enterprise market share figures are based on a survey of 150 technical leaders across AI startups and large enterprises and reflect production workloads, not consumer or developer usage. Consumer-facing market share (Statcounter, Similarweb) tells a different story where ChatGPT remains the leader. Data is refreshed quarterly. If you run into any issues or have a study to suggest, contact us at research@aibehaviorindex.org.