ChatGPT Dominates AI Referral Traffic at 92.4%

ChatGPT commands 92.4% of all tracked large language model (LLM) referral traffic, according to the third AI Traffic Study published by Previsible. The study analyzed 6.77 million LLM-driven sessions, indicating a significant consolidation in the AI discovery market. Monthly LLM sessions grew 9.9 times, reaching 644,478 in May 2026, with ChatGPT being the overwhelming source of this traffic.

AI traffic experienced a notable dip in November 2025, with sessions falling 50% in one month. This decline was primarily driven by a sharp decrease in ChatGPT referrals, which dropped from 448,412 to 213,345. Other AI platforms remained relatively stable during this period. Previsible attributes this volatility to potential model-related changes or product tweaks by the vendor, citing a previous instance where model updates caused ChatGPT to favor specific sources like Wikipedia and Reddit, impacting referral traffic for other sites. Traffic recovered by December 2025, reaching 442,609 sessions.

In terms of market share, the AI landscape has significantly narrowed. In December 2025, ChatGPT held approximately 84% of the market share, followed by Perplexity at 8.9%, Gemini at 4.5%, Copilot at 2.1%, and Claude at 0.6%. Six months later, ChatGPT's dominance has increased to 92.4% of trackable LLM referral traffic, showing a 12.8x growth over 19 months. The study emphasizes that ChatGPT is currently the only LLM generating substantial referral volume at scale, suggesting that optimizing for "AI visibility" necessitates prioritizing ChatGPT.

The study's findings are based on standalone LLM referral traffic and do not include AI discovery features integrated within search engines like Google's AI Overviews. The analysis underscores the critical impact of a single vendor's product decisions on referral traffic, highlighting the inherent volatility in the AI discovery space and the need for strategic planning.