ChatGPT dropped to 46.4% market share in May 2026 — the first time in the platform's history it has fallen below 50%. Google Gemini now holds 27.7% (662M monthly users) and Claude holds 10.3% (245M monthly users). Despite losing its majority, ChatGPT still has 1.1 billion monthly active users, but the structural shift is real and accelerating. OpenAI's DoD partnership announcement in February triggered a measurable spike in uninstalls, contributing to the slide.
The most striking data point: Claude achieved a 13% subscription conversion rate — the highest among all major AI platforms. Users who try Claude are converting to paid at nearly double the rate of competitors. Gemini's growth is driven by Android integration and the WWDC-triggered Apple Siri switchover. The era of ChatGPT as the default AI is over; the AI audience has permanently fragmented into at minimum a three-way race, with different user profiles and use-cases concentrating on different platforms.