More than three and a half years after ChatGPT’s initial release, AI assistants are now used by millions of people worldwide, and the competitive landscape is changing fast. While OpenAI’s chatbot is still the most popular assistant worldwide, globally, its market share has dipped below 50% for the first time as users are migrating between different assistants like Google’s Gemini, Anthropic’s Claude, and xAI’s Grok, according to analytics firm Sensor Tower’s State of AI Report for 2026.