CHATGPT JUST FELL BELOW 50 PERCENT MARKET SHARE FOR THE FIRST TIME IN ITS HISTORY For three and a half years ChatGPT was not just the dominant AI assistant. It was the category. Every competitor was measured against it, every usage chart started with it at the top, and every investor pitch either said we beat ChatGPT or we work with companies that use ChatGPT. That era is over. According to Sensor Tower’s State of AI 2026 report, ChatGPT’s share of global AI assistant users fell to 46.4 percent by the end of May, the first time the number has dipped below 50 since the product launched in November 2022. The crossing happened in March, but the data took time to surface. Gemini and Claude are the main beneficiaries. Both have been gaining ground steadily as Google embedded Gemini across its product surface and Anthropic released Fable 5, its most powerful publicly available model to date. Meanwhile OpenAI has been contending with regulatory scrutiny, leadership turbulence and questions about its long-term business structure. None of this means ChatGPT is dying. Eight hundred million users is not a small number. What it means is that OpenAI no longer has the kind of structural dominance that lets companies stop competing. Rivals now have enough users, enough capital and enough momentum to keep pushing. The market just got genuinely interesting for the first time since 2022. Keywords: ChatGPT market share, AI chatbot competition, Gemini vs ChatGPT, Claude market share