Although ChatGPT remains the leader in terms of user numbers with one billion monthly active users, its market share is falling below 50 percent. Anthropic is gaining ground.
“ChatGPT reached one billion monthly active users in May 2026,” according to the State of AI Report 2026 from market researcher Sensor Tower. In absolute user numbers, ChatGPT remains the leader. However, its market share fell below 50 percent for the first time, standing at 46.6 percent at the end of May. The company is followed by Gemini (28%) and Claude (10%).
Revenue per user
When zooming in on the revenue per individual user, OpenAI has to yield its position to Anthropic. For instance, the average monthly revenue that Claude generates per user via mobile app in the US rose from $0.50 in September to $2.76 in May. ChatGPT, on the other hand, plateaus at $1.74.
In addition, the number of users with a paid subscription at Claude rose by 13 percent, compared to 8 percent at ChatGPT. This is because Anthropic charges higher rates starting at $20 per month, while ChatGPT offers cheaper alternatives. This attracts a broader audience and thus higher user numbers, but the revenue per person is lower as a result.
OpenAI’s billion-dollar loss
Based on leaked financial documents from OpenAI, it appears the company is making billions of dollars in losses annually, according to the Financial Times. Although the company’s rapid revenue growth is clearly evident in the documents—with revenue of $13 billion in 2025 compared to $3.7 billion a year earlier—expenses overshadow these earnings.
Those expenses include investments in research and development, which rose to more than $19 billion in 2025. Furthermore, the cost of running models increased from $2.6 billion in 2024 to $7.5 billion in 2025.