ChatGPT's AI Assistant market share <50% as Gemini and Claude grow
According to Sensor Tower's 2026 State of AI Report, ChatGPT's market share has dipped below 50% for the first time to 46.4%, while Google's Gemini and Anthropic's Claude have grown to 27.7% and 10.3% respectively. Users are increasingly switching assistants, with brand trust and value alignment playing key roles.
More than three and a half years after ChatGPT’s initial release, AI assistants are now used by millions of people worldwide, and the competitive landscape is changing fast. While OpenAI’s chatbot is still the most popular assistant globally, its market share has dipped below 50% for the first time as users are migrating between different assistants like Google’s Gemini, Anthropic’s Claude, and xAI’s Grok, according to analytics firm Sensor Tower’s State of AI Report for 2026.
ChatGPT’s growth has been impressive. It became the fastest app ever to reach 1 billion monthly users, as Sensor Tower reported this month. Notably, OpenAI counts weekly active users, and it last reported 900 million of them in February. The chatbot still remains the most popular AI assistant worldwide with over 1.1 billion monthly users, followed by Gemini with 662 million and Claude with 245 million.
Image Credits:Sensor Tower
Until January, ChatGPT commanded over 50% market share, but by May’s end, it had fallen to 46.4% thanks to the rise of Gemini (27.7%) and Claude (10.3%). Other assistants, including Grok, Perplexity, DeepSeek, and Meta AI, have less than 5% market share.
Image Credits:Sensor Tower
Sensor Tower’s State of AI Report also found that users are increasingly willing to switch between assistants. Specific events appear to accelerate that behavior: OpenAI’s deal with the U.S. Department of Defense (DoD) in February triggered a measurable spike in uninstalls, for example — suggesting brand trust and values alignment matter to users, not just features. While Gemini’s momentum is largely due to its integration with Google’s broader ecosystem of tools, Anthropic’s Claude has gained a strong reputation for productivity use cases and is closing in on ChatGPT’s user-retention rate.