Three and a half years after the launch of ChatGPTthe AI assistant market continues to grow, but the leader is losing ground. The chatbot OpenAI remains the most popular globally, but its market share has fallen below 50% for the first time according to other options such as Geminiof Googleand Claudeof Anthropicare being consolidated among users, according to the report ‘State of AI Report 2026’ from the analysis firm Sensor Tower.
Among other things, ChatGPT can boast of being the app that faster it has reached 1,000 million monthly usersa milestone it achieved in July 2025, according to Sensor Tower. The chatbot arrived at the end of May with more than 1.1 billion of monthly users, followed by Gemini, with 662 millionand Claude, with 245 million.
OpenAI, for its part, counts weekly active users, not monthly, and the last figure it reported, in February, was 900 million.
The majority of attendees have quotas of less than 5%
Until January, ChatGPT maintained a market share of over 50%, but by the end of May it had fallen to 46.4% for the advance of Gemini, with a 27.7%and Claude, with a 10.3%. Other attendees, including Grok, Perplexity, DeepSeek and Meta AI, have shares of less than 5%.
The Sensor Tower report also notes that users are increasingly willing to change assistantssometimes motivated by specific events. OpenAI’s agreement with the US Department of Defense in February caused, for example, a spike in uninstalls, suggesting that brand trust and affinity matter to users, not just features. While Gemini’s momentum is largely due to its integration with the Google tools ecosystemAnthropic’s Claude has built a strong reputation in productivity use cases and is approaching ChatGPT’s user retention rate.
In the first half of 2026, users are on track to download almost 2.3 billion AI applications and to spend more than 4.2 billion dollars in them, according to Sensor Tower estimates. The figure contrasts with the 1.83 billion dollars of spending in the first half of 2025, a jump that suggests the industry is focusing on monetization. That said, both download and spending growth have slowedan indication that the market could be maturing although the absolute numbers continue to increase.
Claude has the best rate of paying users
By regions, Asia recorded the first drop in downloads, 3.3%in the first quarter of 2026, driven by declines in China and India. Although it leads the world in total downloads, Asia trails North America and Europe in in-app spendinga relevant difference for companies that must decide where to invest in premium features and monetization.
In USAusers are leaning towards AI assistants for productivity tasks and spend more on premium features. Across all platforms, average revenue per user has grown across the industry, but Claude stands out in particular. 13% of Anthropic users pay for a subscription, the highest conversion rate on the market.
The report does not give a specific breakdown for Spainbut it does mention Europe as one of the regions where Gemini is gaining presence thanks to the push of Android and the Google ecosystem.
Sensor Tower estimates that time spent on AI applications will have increased by 17.2 billion hours in the first half of 2025 at about 36 billion hours in the first half of 2026. The three main attendees concentrate the 89% of time spent on AI assistant applications. Meanwhile, adjacent categories such as AI companion apps or AI content generation apps remain fragmented and wide open to competition.