ChatGPT’s Global Market Share Falls Below 50% for the First Time

According to Sensor Tower’s 2026 AI State Report , ChatGPT has been the world’s most popular AI assistant for over three and a half years, reaching 1 billion monthly active users—the fastest app to do so. However, its global market share fell below 50% for the first time, dropping to 46.4% by late May 2026 as Google’s Gemini (27.7%) and Anthropic’s Claude (10.3%) gained ground, while other assistants such as Grok, Perplexity, DeepSeek and Meta AI each remained under 5%.

ChatGPT’s weekly active users hit 900 million in February, and its monthly active users now exceed 1.1 billion, still outpacing Gemini (662 million) and Claude (245 million). Sensor Tower estimates that AI‑assistant app downloads will approach 2.3 billion in the first half of 2026, with total in‑app revenue surpassing $4.2 billion—up from $1.83 billion in the same period of 2025—indicating a move from pure user growth to monetisation, though growth rates are slowing.

User Migration and Trust Factors

Sensor Tower notes a growing willingness among users to switch between assistants. A notable spike in ChatGPT uninstallations followed OpenAI’s February agreement with the U.S. Department of Defense, suggesting that brand trust and value‑alignment can outweigh functional advantages.

Advertising Experiments

In February 2024 OpenAI began testing commercial ads within ChatGPT. By May, 17% of daily users were exposed to ads, with software & shopping, media & entertainment, and food & beverage being the largest advertiser categories. Integration with shopping platforms directs traffic to retailers such as Target, Walmart and Costco, while Amazon blocked ChatGPT’s web crawler, limiting referral traffic.

Regional Dynamics

Asia experienced a 3.3% decline in downloads in Q1 2026—the first drop in the region—driven by reduced activity in China and India. Although Asia still leads global download volume, its in‑app revenue lags behind North America and Europe, a key consideration for companies planning feature roll‑outs and monetisation strategies.

U.S. users increasingly use AI assistants for productivity and are willing to pay for premium features; Anthropic reports a 13% subscription conversion rate for Claude, the highest in the industry, highlighting a potential metric for sustainable profitability.

Overall, the AI‑assistant market is entering a “three‑horse tug‑of‑war” among ChatGPT, Gemini, and Claude, with user time spent on the top three apps accounting for 89% of total usage. The sector’s rapid growth, diversification of ad revenue, and regional variations suggest both opportunities and challenges for firms that can quickly adapt.