OpenAI’s ChatGPT remains the world’s most popular AI assistant, but its dominance is beginning to face real pressure, as rivals such as Google Gemini, Anthropic Claude, xAI Grok, Perplexity, DeepSeek, and Meta AI grow their presence in the market.
TL;DR
- ChatGPT’s global AI assistant market share fell to 46.4% by the end of May 2026.
- Gemini rose to 27.7%, while Claude reached 10.3%.
- Sensor Tower estimates AI app spending could cross $4.2 billion in H1 2026.
- ChatGPT still leads with over 1.1 billion monthly users.
More than three and a half years after ChatGPT’s launch, OpenAI’s chatbot has seen its global AI assistant market share drop below 50% for the first time, according to Sensor Tower’s State of AI Report 2026 cited by TechCrunch. ChatGPT held over 50% share until January 2026, but by the end of May, it had fallen to 46.4%.
Despite the decline, ChatGPT continues to lead the market with more than 1.1 billion monthly users. Google’s Gemini follows with 662 million monthly users, while Anthropic’s Claude stands at 245 million. Gemini’s market share has climbed to 27.7%, while Claude now commands 10.3%. Other AI assistants, including Grok, Perplexity, DeepSeek, and Meta AI, each remain below 5%.
The milestone does not suggest ChatGPT is slowing down in absolute terms. Reuters reported earlier this month that ChatGPT crossed 1 billion global monthly active app users, becoming the fastest app to reach that mark, based on Sensor Tower estimates.
OpenAI also said earlier this year that “ChatGPT is where people start with AI,” adding that the product had more than 900 million weekly active users and over 50 million consumer subscribers. The company said people use ChatGPT to learn, write, plan, and build, while product improvements have focused on faster responses, reliability, safety, and performance.
However, the market is clearly becoming more competitive. Sensor Tower’s report suggests users are increasingly willing to switch between AI assistants, especially as rivals improve their productivity, search, coding, and ecosystem integrations. Gemini’s growth appears to be helped by its place across Google’s broader product ecosystem, while Claude continues to gain attention for productivity-focused use cases.
This shift also comes as spending on AI apps continues to rise. Sensor Tower said global time spent on generative AI apps is projected to reach 36 billion hours in H1 2026, up from 17.2 billion hours in H1 2025. The firm also said AI app in-app purchase revenue is on track to exceed $4 billion in H1 2026.
TechCrunch reported that people are on pace to download nearly 2.3 billion AI apps and spend over $4.2 billion on them in the first half of 2026, compared with $1.83 billion in spending during H1 2025. Still, growth rates for downloads and spending have slowed, indicating that the AI assistant market may be maturing even as overall usage keeps expanding.
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OpenAI’s monetization strategy is also evolving. According to Sensor Tower data cited by TechCrunch, OpenAI began experimenting with ads in ChatGPT in February 2026 and had scaled exposure by May, when an average of 17% of daily users were reportedly being served ads. Software and shopping were the largest advertiser categories so far.
For OpenAI, the story is not a loss of leadership, but a sign that the AI assistant race is moving from early domination to platform competition. ChatGPT remains the largest player, yet users now have credible alternatives that are gaining scale, retention, and monetization traction.
