For the first time since its launch, ChatGPT’s market share has slipped below 50%. The artificial intelligence (AI) platform, however, continues to dominate the market.

Hit by Google Gemini's continued expansion and Claude's recent growth, ChatGPT's share of the AI assistant market fell below 50% for the first time in March 2026, as per a report published by market intelligence firm Sensor Tower.

By May, ChatGPT held a 46% share, ahead of Google Gemini (28%) and Anthropic’s Claude (10%), it said.


Driving the shift

As per the report, Claude’s strong growth in certain markets, including the US, where the demand for coding and deep research capabilities is higher, dented ChatGPT’s market share.

Even more users shifted from ChatGPT after OpenAI signed agreements to work with the US Department of War in late February. Consequently, by May 2026, Claude's market share in the US had reached nearly 14%, up from just 5% in December 2025.

In the US, ChatGPT uninstalls surged 200% following OpenAI's agreement with the US government. Many users switched to Claude.

ChatGPT recently crossed 1 billion global monthly active app users, becoming the fastest app ever to reach the milestone, ‌according to estimates from Sensor Tower. ChatGPT ⁠reached 1 billion MAUs in May, roughly three years after launch, surpassing the pace set by apps such as Google Maps, TikTok, Instagram and YouTube.

Other AI trends to know about:

  • ChatGPT began testing ads with select users in February, before expanding availability in March and April. By the end of May, both the total number of ads and the number of users seeing ads had increased roughly seven-fold compared to the first week of March.
  • Shopping and Software brands are early adopters of ChatGPT advertising, using the platform to reach users during the research and discovery phase. Together, these two categories account for nearly half of all ads on ChatGPT.
  • Global time spent is projected to more than double Year-on-Year in H1 2026, rising from 17.2 billion hours to 36 billion hours, equivalent to more than four hours for every person on Earth.
  • Asia recorded its first decline in AI app downloads after 13 consecutive quarters of growth, with downloads falling 3.3% in Q1 2026. The Middle East also declined, while every other region posted growth, led by Latin America and Europe.
  • The United States dominates the generative AI app market, accounting for nearly 60% of global downloads and 85% of in-app purchase revenue.