ChatGPT's share of the AI assistant market drops below 50% for the first time

ChatGPT's share of the global AI assistant market has fallen below 50% for the first time. OpenAI's service held more than half of the market as recently as January, but by the end of May, its share had slipped to 46.4%. Despite the decline, ChatGPT remains the largest AI assistant in the world, with a monthly user base of more than 1.1 billion.

The figures come from Sensor Tower's State of AI 2026 report, cited by TechCrunch. The report tracks user behavior across major AI services and offers one of the most detailed pictures of how the market is shifting in 2026.

How the market breaks down

Google's Gemini sits in second place with 662 million users and a 27.7% share. Anthropic's Claude comes in third, with 245 million users and a 10.3% share. The rest of the field, including xAI's Grok, Perplexity, DeepSeek, and Meta AI, each holds less than 5%. The three largest services together account for roughly 89% of all time users spend inside AI assistants.

The drop in ChatGPT's share has less to do with user churn and more to do with users moving more freely between services. According to Sensor Tower, specific events can sharply accelerate that pattern. After OpenAI signed a contract with the U.S. Department of Defense in February, app uninstalls jumped by 295%. The data suggests that users now care not just about features, but also about company reputation and values. Gemini's growth has been driven in large part by its integration into Google's broader ecosystem, while Claude has built a reputation as a tool for work-related tasks and is now closing in on ChatGPT in terms of user retention.

For the first half of 2026, Sensor Tower estimates that users will download around 2.3 billion AI apps and spend more than $4.2 billion on them, compared with $1.83 billion in the same period of 2025. The numbers point to a clear shift in industry focus from raw audience growth to monetization. At the same time, the pace of both downloads and spending is slowing down, a sign that the market is gradually approaching saturation.

Sensor Tower also singles out Claude for one specific reason. 13% of its users have converted to a paid subscription, the strongest conversion rate in the industry and a metric likely to attract the attention of investors going forward.