ChatGPT Under Pressure: Market Share Falls Below 50%

ChatGPT Loses Ground to Competition

More than three and a half years after its launch, OpenAI's ChatGPT, which has long dominated the AI assistant market, has seen its market share drop below 50% for the first time. According to Sensor Tower's "State of AI 2026" report, this decline is attributed to the rise of competitors such as Google's Gemini, Anthropic's Claude, and xAI's Grok. Although ChatGPT remains the most popular AI assistant with over 1.1 billion monthly users, its market share fell to 46.4% in May, down from over 50% in January. Gemini and Claude, with respective market shares of 27.7% and 10.3%, are gradually gaining ground.

ChatGPT was the fastest application to reach 1 billion monthly users, a feat reported by Sensor Tower this month. OpenAI also recorded 900 million weekly active users in February, highlighting the continued popularity of the app despite increasing competition. Other assistants, such as Perplexity, DeepSeek, and Meta AI, hold less than 5% market share but contribute to the fragmentation of the AI assistant landscape.

Impact of Strategic Decisions

OpenAI's agreement with the U.S. Department of Defense in February coincided with a rise in uninstalls, suggesting that brand trust and alignment of values are crucial for users. Meanwhile, Gemini benefits from its integration into the broader Google tool ecosystem, and Claude stands out for its efficiency in productivity tasks. Users are showing an increasing willingness to switch assistants, influenced by these factors.

Growth and Monetization of the AI Market

In the first half of 2026, users are on track to download nearly 2.3 billion AI applications, with spending reaching $4.2 billion. This represents a significant increase from the $1.83 billion spent in the first half of 2025, although the growth in downloads and spending has slowed. This indicates that the market may be maturing, even as absolute figures continue to rise.

Regionally, Asia recorded a first decline in downloads of 3.3% in the first quarter of 2026, due to drops in China and India. While Asia leads globally in total downloads, it lags behind North America and Europe in terms of in-app spending. In the United States, users are turning to AI assistants for productivity tasks and spending more on premium features. Anthropic's Claude stands out with 13% of its users paying for a subscription plan, a conversion rate that leads the industry.

Advertising and E-commerce

OpenAI began experimenting with advertising in ChatGPT in February. According to Sensor Tower, the company has gradually increased the number of ads, as well as the share of users who see them. In May, an average of 17% of daily users were exposed to ads. The largest advertiser categories include software, shopping, media and entertainment, as well as food and dining.

ChatGPT is deepening its shopping integrations, sending more referral traffic to retailers like Target, Walmart, and Costco. Amazon, which has blocked ChatGPT's crawling bots, has seen stagnant referral traffic from the platform as a result. This creates an opening for others. Sites like Walmart have integrated their own AI assistants to help shoppers find products. While Amazon's Rufus has experienced stagnant user growth, Walmart's Spark has gained traction.

Time Spent on AI Applications

Sensor Tower estimates that time spent on AI applications will have increased from 17.2 billion hours in the first half of 2025 to approximately 36 billion hours in the first half of 2026. The top three assistants account for 89% of the time spent on AI assistant applications. Meanwhile, adjacent categories such as AI companions or AI content generation applications remain fragmented and largely open to competition, representing both a risk and an opportunity for those who move first.