According to SimilarWeb, ChatGPT's global web traffic share fell from 77.6% in May 2025 to 53.7% in April 2026, a 24% drop in 12 months. Competitors like Google's Gemini (from 7.27% to 26.7%) and Claude (from 1.37% to 7.95%) grew significantly. However, web traffic share only measures consumer visits, not API calls or enterprise contracts. The Ramp AI Index, tracking paid AI subscriptions across 50,000+ U.S. businesses, reported a stunning reversal: for the first time, more companies pay for Anthropic (34.4%) than OpenAI (32.3%). Anthropic's growth is driven by Claude Code, an agentic coding tool. OpenAI argued that its largest enterprise deals bypass corporate cards, not captured by Ramp's methodology. Secondary markets price Anthropic at ~$1 trillion (Forge Global), above OpenAI's $880 billion, reflecting investor belief in the trend. OpenAI faces risks from Anthropic's pricing and service quality, while Google's Gemini benefits from Android integration. The AI market is fragmenting, with OpenAI's first-mover advantage fading.

Key facts

• Web share: ChatGPT 53.7%, Gemini 26.7%, Claude 7.95% in April 2026
• Ramp Index: Anthropic (34.4%) surpasses OpenAI (32.3%) in business adoption for first time
• Anthropic's secondary valuation ~$1T, OpenAI ~$880B on Forge Global
• Claude Code drives Anthropic growth, with high per-engineer API costs at firms like Uber
• OpenAI argues its biggest enterprise deals are via contracts, not credit cards