According to Sensor Tower’s 2026 report, ChatGPT’s share of the AI assistant market fell below 50% for the first time since its launch, reaching 46.4% by late May 2026. The report also notes that ChatGPT remains the largest individual assistant with 1.1 billion monthly users. Google’s Gemini follows with 662 million monthly users, and Anthropic’s Claude has 245 million monthly users.
What happened and when
- The decline in market share occurred by late May 2026, marking the first time ChatGPT no longer holds a majority since its debut.
- Sensor Tower attributes part of the shift to users freely switching among assistants, with Gemini and Claude absorbing much of the share that slips from ChatGPT.
Why this matters
The analysis highlights that ChatGPT’s initial first-mover advantage rested largely on superior model performance, and that performance gaps have narrowed. When multiple assistants deliver comparable answers, competition shifts away from raw model quality toward factors such as ecosystem, user habits, and trust. As a result, market share naturally fragments.
The competition’s new focal point
Sensor Tower suggests the decisive contest is moving beyond chatbots to “agents”: systems that manage more complex, longer-term tasks, provide automation, and deliver personalized agent behaviors. Success in the next phase will favour platforms that enable agent capabilities rather than only producing high-quality conversational responses.
Conclusion
ChatGPT’s loss of a majority is not primarily due to a single superior rival, but to a broader change in where value is created in the market. As assistants cease to be the sole battleground and agents gain prominence, further fragmentation of market share is likely until the winning agent-based approaches emerge.
