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

More than three and a half years after ChatGPT first launched, AI assistants are now used by millions globally, and the competitive landscape is shifting rapidly. Although OpenAI’s chatbot remains the most popular assistant worldwide, its market share has slipped below 50% for the first time, as users increasingly migrate between platforms such as Google’s Gemini, Anthropic’s Claude, and xAI’s Grok, according to analytics firm Sensor Tower’s State of AI Report for 2026.

ChatGPT’s growth has been remarkable. It became the fastest app ever to reach 1 billion monthly users, as Sensor Tower reported this month. Notably, OpenAI tracks weekly active users, and it last reported 900 million of them in February. The chatbot still leads globally with over 1.1 billion monthly users, followed by Gemini with 662 million and Claude with 245 million.

Image Credits:Sensor Tower

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

Image Credits:Sensor Tower

Sensor Tower’s State of AI Report also found that users are increasingly willing to switch between assistants. Specific events appear to accelerate this behavior: OpenAI’s deal with the U.S. Department of Defense (DoD) in February triggered a measurable spike in uninstalls, for example, suggesting that brand trust and values alignment matter to users, not just features. While Gemini’s momentum largely stems from its integration with Google’s broader ecosystem, Anthropic’s Claude has built a strong reputation for productivity use cases and is closing in on ChatGPT’s user-retention rate.

In the first half of 2026, people are on track to download nearly 2.3 billion AI apps and spend over $4.2 billion on them, according to Sensor Tower estimates. That compares to $1.83 billion in spending during H1 2025, a jump that suggests the industry is shifting focus from pure growth toward monetization. That said, both download and spend growth rates have slowed, indicating that the market may be maturing even as absolute numbers continue to climb.

Regionally, Asia recorded its first download decline of 3.3% in Q1 2026, driven by dips in China and India. Despite leading globally in total downloads, Asia trails North America and Europe in in-app spending, a split that matters for companies deciding where to invest in premium features and monetization.

Image Credits:Sensor Tower

In the U.S., users are gravitating toward AI assistants for productivity tasks and spending more on premium features. Across platforms, average revenue per user has grown industry-wide, but Claude is standing out. Thirteen percent of Anthropic’s users are paying for a subscription plan, a conversion rate that leads the field and will be a key metric for investors evaluating which AI businesses are building lasting revenue.

Sensor Tower estimates that hours spent on AI apps will have increased from 17.2 billion hours in H1 2025 to roughly 36 billion hours in H1 2026. The top three assistants command 89% of time spent on AI assistant apps. Meanwhile, adjacent categories like AI companions or AI content-generation apps remain fragmented and wide open to competition, representing both a risk and an opportunity depending on which players move first.

Ads and shopping

OpenAI began experimenting with ads in ChatGPT in February. According to Sensor Tower, the company has gradually scaled the number of ads and the share of users who see them. By May, an average of 17% of daily users were being served ads, a figure to watch as ChatGPT’s monetization strategy evolves beyond subscriptions.

Image Credits:Sensor Tower

Software and shopping are the largest advertiser categories in ChatGPT so far, followed by media and entertainment, and food and dining.

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

That creates an opening for others. Sites like Walmart have embedded their own AI assistants to help shoppers find products. While Amazon’s Rufus has seen flat user growth, Walmart’s Spark has been gaining 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 didn’t, hinting that on-platform AI can meaningfully influence purchasing behavior when users actually engage with it.