ChatGPT’s market share drops below 50% for the first time

More than three and a half years after ChatGPT’s initial release, AI assistants are now being used by millions of people around the world, and the competitive landscape is changing rapidly. While OpenAI’s chatbot remains the most popular assistant worldwide, its market share has dropped below 50% for the first time as users switch between different assistants like Google’s Gemini, Anthropic’s Claude, and xAI’s Grok, according to analytics firm Sensor Tower’s 2026 State of AI report.

ChatGPT’s growth has been impressive. It became the fastest app ever to reach one billion monthly users, called Sensor Tower I mentioned This month. Notably, OpenAI counts the number of active users weekly, which was recently reported 900 million of them in February. The chatbot remains the most popular AI assistant worldwide with over 1.1 billion monthly users, followed by Gemini with 662 million and Cloud with 245 million.

Until January, ChatGPT held more than 50% of the market share, but by the end of May, this share had dropped to 46.4% thanks to the rise of Gemini (27.7%) and Claude (10.3%). Other assistants, including Grok, Perplexity, DeepSeek, and Meta AI, have a market share of less than 5%.

Sensor Tower’s State of AI report also found that users are increasingly willing to switch between assistants. Specific events appear to be accelerating this behavior: OpenAI’s agreement with the US Department of Defense (DoD) last February sparked… Measurable rise in uninstallsFor example – suggesting brand trust and values ​​alignment is important to users, not just features. While Gemini’s momentum is largely due to its integration with the broader Google tools ecosystem, Anthropic’s Claude has gained a strong reputation for productivity use cases and is approaching ChatGPT’s user retention rate.

In the first half of 2026, people are poised to download nearly 2.3 billion AI apps and spend more than $4.2 billion on them, according to Sensor Tower estimates. That compares to $1.83 billion in spending in the first half of 2025 — a jump that suggests the industry is shifting its focus from pure growth to monetization. However, growth rates of downloads and spending have slowed, an indication that the market may be maturing even as absolute numbers rise.

Regionally, Asia recorded its first download decline of 3.3% in Q1 2026, driven by declines in China and India. Despite leading globally in total downloads, Asia lags behind North America and Europe when it comes to in-app spending – an important division for companies deciding where to invest in premium features and monetization.

In the US, users are gravitating toward AI assistants for productivity tasks and spending more on premium features. Across platforms, average revenue per user has risen industry-wide, but Cloud stands out. Thirteen percent of Anthropic users pay for a subscription plan — a conversion rate that leads the industry and will be a metric worth watching for investors evaluating AI companies that generate consistent revenue.

Sensor Tower estimates that hours spent on AI apps will rise from 17.2 billion hours in the first half of 2025 to nearly 36 billion hours in the first half of 2026. The top three assistants spend 89% of time on AI assistant apps. Meanwhile, adjacent categories like AI companions or AI content creation apps remain fragmented and widely open to competition, representing both risk and opportunity depending on which players move first.

OpenAI began experimenting with ads in ChatGPT in February. According to Sensor Tower, the company has gradually expanded the number of ads, along with the percentage of users who view them. By May, an average of 17% of daily users were being shown ads — a number to monitor as ChatGPT’s monetization strategy evolves beyond subscriptions.

Programmatic and Shopping are ChatGPT’s largest advertiser categories by far, followed by Media & Entertainment and Food & Dining.

As ChatGPT deepens its shopping integrations, it is increasingly sending referral traffic to retailers like Target, Walmart, and Costco. Amazon, which blocked ChatGPT’s web crawlers, has seen referral traffic from the platform stagnate as a result.

This creates opportunity for others. Sites like Walmart have embedded their own AI assistants to help shoppers find products. While Amazon’s Rufus has seen steady growth in users, Walmart’s Spark is gaining more ground. Sensor Tower also noted that Amazon shoppers who used Rufus spent more time in the app and converted at higher rates than those who did not, suggesting that AI on the platform can significantly influence purchasing behavior when users actually interact with it.