NEW YORK, Nov. 9, 2026 | ChatGPT is winning back share of the AI chatbot market after hitting a record low in June, according to new data from AI growth firm Graphite and market intelligence firm Similarweb reported by Forbes on Monday. ChatGPT held 81.2% of worldwide AI chatbot sessions in September 2026, up from an all-time low of 80.42% in June, as Claude's sessions grew roughly 20-fold in a year.
What the Graphite and Similarweb Data Shows
ChatGPT's sessions across its mobile app and website reached an all-time high of 61 billion in September, up 3% from August and 24% from September 2025, according to Forbes. Its U.S. share rose from 79.64% in June to 80.68% in September. The recovery is modest next to its peak: ChatGPT held 96.11% of worldwide sessions in December 2024. No competitor has reached 10% worldwide share.
Claude grew fastest. Its sessions rose from 271 million in September 2025 to 5.4 billion in September 2026, and its worldwide share climbed from about 0.72% in January to 7.2% in September. Gemini's sessions nearly tripled, from 1.3 billion to 3.7 billion, and its share moved from 4.15% to 4.92% over the same January to September stretch. Grok, Perplexity and DeepSeek all lost share. Graphite CEO Ethan Smith credited ChatGPT's rebound to the "cumulative sum of various product improvements and enhancements." D.A. Davidson analyst Gil Luria said ChatGPT's early lead built a large base of consumers who "are still happy using ChatGPT." Our AI usage statistics guide tracks how adoption is moving more broadly.
Analysis: A Market Leader and a Fast Climber
Both things in the data are true at once. ChatGPT's share gain since June is under one percentage point, but it sits on a base of 61 billion monthly sessions. Claude's 7.2% share now sits ahead of Gemini's 4.92% by this measure, a shift from January, when Gemini led.
An October Similarweb dataset cited by Forbes adds context on loyalty: 64.1% of ChatGPT users used only ChatGPT, compared with 54% for Gemini and 26.4% for Claude. That suggests many Claude users also use other assistants, which matters for teams choosing tools, since staff may already rely on more than one. Forbes did not detail the study's methodology, and session counts measure usage, not revenue or paid seats, so the figures say who is being used most, not who is earning most.
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Frequently Asked Questions
What is ChatGPT's market share in 2026?
ChatGPT held 81.2% of worldwide AI chatbot sessions in September 2026, up from an all-time low of 80.42% in June, according to Graphite and Similarweb data reported by Forbes. Its U.S. share was 80.68%.
How fast is Claude growing?
Claude's sessions rose from 271 million in September 2025 to 5.4 billion in September 2026, and its worldwide share grew from about 0.72% in January 2026 to 7.2% in September, according to Graphite and Similarweb data reported by Forbes.