Headline: ChatGPT Market Share Dips Below 50% Amid Rising AI Assistant Competition

ChatGPT's global market share in AI assistant applications fell below 50% for the first time in three and a half years, reaching 46.4% by May 2026, according to Sensor Tower's "State of AI Industry Report 2026." This marks a significant shift from single dominance to a three-way competition, with Google's Gemini and Anthropic's Claude gaining substantial ground. Despite the decline from over 50% in January 2026, ChatGPT maintains its lead with 1.1 billion monthly active users (MAU). Google Gemini now holds 27.7% of the market with 662 million MAU, while Anthropic Claude captures 10.3% with 245 million MAU. The industry's focus is shifting towards monetization, with global AI app user spending projected to hit $4.2 billion in the first half of 2026, up from $1.83 billion in the first half of 2025. OpenAI began testing ads in ChatGPT in February 2026, with 17% of daily users currently exposed.