ChatGPT’s dominance in the global AI assistant market has slipped below 50% for the first time since its inception. This decline is attributed to increased competition from Google’s Gemini and Anthropic’s Claude, challenging OpenAI’s longstanding position as a frontrunner in the AI chatbot sector since late 2022.
As per Sensor Tower’s State of AI Report for 2026, ChatGPT previously held over 50% of the market share until January, but by the end of May, its share had decreased to 46.4%. Gemini now claims 27.7% of the market, with Claude holding 10.3%. Other AI assistants like Grok, Perplexity, DeepSeek, and Meta AI each have market shares below 5%.
Despite the decline, ChatGPT remains the most widely used AI assistant globally, surpassing one billion monthly active users at a record pace. Gemini boasts 662 million monthly users, while Claude has 245 million users.
The report indicates a growing trend of users switching between AI assistants, with specific events influencing this behavior. For instance, OpenAI’s collaboration with the US Department of Defense in February led to a noticeable increase in uninstalls, emphasizing the importance of brand trust and alignment with user values in addition to product quality.
Gemini’s success is partly due to its integration into Google’s extensive range of tools. Claude has gained recognition for its productivity applications and is approaching ChatGPT’s user retention rate. Noteworthy is Anthropic’s high conversion rate, with 13% of its users opting for subscription plans, leading the industry.
In the first half of 2026, the download of AI apps is projected to reach nearly 2.3 billion, with a spending estimate of over $4.2 billion, compared to $1.83 billion in the same period in 2025. However, the growth rates for downloads and spending have slowed, suggesting market maturation despite increasing overall figures. The estimated time spent on AI apps has surged from 17.2 billion hours in H1 2025 to around 36 billion hours in H1 2026, with the top three assistants accounting for 89% of total usage time.
Regionally, Asia experienced a 3.3% decrease in downloads in the first quarter of 2026, primarily driven by declines in China and India. Although Asia leads in global downloads, North America and Europe surpass it in in-app expenditures.
OpenAI ventured into advertising within ChatGPT in February, with an average of 17% of daily users being exposed to advertisements by May. The most prominent categories of advertisers include software and shopping, followed by media and entertainment, and food and dining.
