OpenAI market share dips below 50% for the first time

For the first time, ChatGPT’s share of the AI assistant market has fallen below 50% worldwide. According to Sensor Tower, the analytics firm that published the State of AI Report for 2026, ChatGPT commanded over 50% of the market until January, but its share fell to 46.4% by May’s end. Users are increasingly migrating between different AI assistants globally, leading to a more distributed competitive landscape:

• ChatGPT (OpenAI): 46.4% market share (with over 1.1 billion monthly users)
• Gemini (Google): 27.7% market share (with 662 million monthly users)
• Claude (Anthropic): 10.3% market share (with 245 million monthly users)

Other assistants, including Grok, Perplexity, DeepSeek, and Meta AI, have less than 5% market share. While ChatGPT remains the assistant with the most users globally, the user metrics highlight different engagement tracking: OpenAI reported 900 million weekly active users in February, while its monthly user base now stands at over 1.1 billion.

User loyalty is proving highly sensitive to corporate actions. Sensor Tower’s report indicates that specific events appear to accelerate user migration. For instance, OpenAI’s deal with the U.S. Department of Defense in February triggered a measurable spike in uninstalls, suggesting that brand trust and values alignment are actively influencing user retention. Meanwhile, Gemini’s momentum is supported by its integration with Google’s broader ecosystem, and Claude has gained ground on productivity use cases.

As user growth rates decelerate, the AI industry is shifting its focus from pure growth toward monetization. Globally, users are on pace to download nearly 2.3 billion AI apps and spend over $4.2 billion on them in H1 2026, compared to $1.83 billion in H1 2025. Sensor Tower estimates that the hours spent on AI apps will have increased from 17.2 billion hours in H1 2025 to roughly 36 billion hours in H1 2026, with the top three assistants commanding 89% of that time. To capitalize on this, OpenAI began experimenting with ads in February, scaling them to serve an average of 17% of daily users by May. Meanwhile, thirteen percent of Anthropic’s users are paying for a subscription plan.

This monetization push faces regional variations. In Q1 2026, Asia recorded its first download decline of 3.3%, driven by dips in China and India. Although Asia leads globally in total downloads, the region trails North America and Europe in in-app spending. This geographic split is forcing developers to carefully target where they deploy premium features.

Why it matters

The decline in ChatGPT’s dominance marks a transition from the “growth at all costs” phase of the AI boom to a competitive, monetization-focused market where user loyalty is no longer guaranteed.