ChatGPT falls below 50% market share despite its lead

The lead is intact. The gap is shrinking. ChatGPT’s share of the AI assistant market has dipped below 50%, yet it remains the most used chatbot worldwide.

According to Sensor Tower’s State of AI Report 2026, ChatGPT stood at 46.4% market share by the end of May. The report also confirms that OpenAI’s chatbot continues to lead on absolute usage, even as competition intensifies.

What changed in the market

Rivals have tightened the race. Google’s Gemini has grown to 27.7% and Anthropic’s Claude to 10.3%, while other assistants such as Grok, Perplexity, DeepSeek and Meta AI each hold under 5%. Sensor Tower notes that people are switching between assistants based on features, integrations and trust. This suggests user preferences are becoming more fluid as products evolve.

Users and usage at scale

Despite a smaller share, ChatGPT’s footprint is immense. The report cites more than 1.1 billion monthly users for ChatGPT, with Gemini at about 662 million and Claude around 245 million. Time spent in AI apps is forecast to climb from 17.2 billion hours in the first half of 2025 to nearly 36 billion hours in the first half of 2026. This points to deepening, everyday engagement rather than a passing trend.

Money and monetisation

Consumer spending on AI apps is accelerating. Sensor Tower estimates almost $4.2 billion in the first half of 2026, up from $1.83 billion a year earlier. OpenAI has expanded advertising tests inside ChatGPT, with around 17% of daily users estimated to have seen ads by May.

The report adds that ChatGPT is pushing more referral traffic to retailers such as Target, Walmart and Costco, while Amazon’s tighter crawler rules are associated with flatter referrals from the platform.

Regional shifts worth watching

Asia recorded a 3.3% decline in downloads in the first quarter of 2026, led by dips in China and India. Even so, Asia still leads in total downloads, while North America and Europe generate comparatively higher in-app spending. These differences hint at varied adoption patterns and business models across regions.

What it means

The headline is a share story, not a collapse. The AI assistant market is expanding quickly, so ChatGPT can add users even as its share slips. Strong challengers, default placements on devices and rapid feature cycles are fragmenting attention.

For users and businesses, the takeaway is clear: the future looks multi-assistant, and performance, trust and ecosystem fit will matter more than brand alone.