OpenAI's ChatGPT has lost its majority share of the global AI assistant market for the first time, according to analytics firm Sensor Tower. The firm published its State of AI Report 2026, revealing that ChatGPT controlled more than half of the AI assistant market until January 2026. By the end of May, its share had declined to 46.4%. This decline comes as rivals such as Google's Gemini, Anthropic's Claude, and Elon Musk-backed Grok continue to attract users. Despite the drop, the report notes that OpenAI's chatbot still has over 1.1 billion monthly active users, making it the most popular AI assistant in the market.
Gemini Emerges as ChatGPT's Biggest Challenger
Google's Gemini has been the biggest beneficiary of the changing market. According to the Sensor Tower report, Gemini now holds 27.7% of the AI assistant market, making it the second-largest AI chatbot platform worldwide. The growth has largely been driven by Gemini's integration across Google's ecosystem of products and services, including Google Search, Gmail, Android, and Workspace, helping the platform gain traction. With 662 million monthly users, Gemini has established itself as OpenAI's closest rival.
Anthropic's Claude Gains Ground
Anthropic's Claude is also taking users away from ChatGPT. The report found that Claude's market share reached 10.3%, while its monthly user base grew to 245 million. Claude is also leading in paid subscriptions. According to the report, 13% of Anthropic's users pay for premium plans, the highest conversion rate among major AI assistant platforms.
Grok, Perplexity, DeepSeek, and Meta AI Continue to Grow
While Gemini and Claude account for most of the shift in market share, other AI assistants are also expanding their user bases. Sensor Tower stated that Grok, Perplexity, DeepSeek, and Meta AI each hold less than 5% of the market. However, together they are contributing to a more competitive AI landscape.
Sensor Tower estimates that users will download nearly 2.3 billion AI apps in the first half of 2026. Consumer spending on AI apps is expected to exceed $4.2 billion during the same period, more than double the $1.83 billion recorded a year earlier. The report also estimates that time spent on AI apps will increase from 17.2 billion hours in the first half of 2025 to about 36 billion hours in the first half of 2026.
