Previsible analyzed 6.77 million LLM-driven sessions across 166 GA4 properties from November 2024 through May 2026. The headline number: ChatGPT now commands 92.4% of all standalone AI referral traffic, delivering 610,910 sessions in May 2026 alone — up from 65,249 in November 2024, a 9.9x increase in 19 months.

The platform reshuffling beneath that number is strategically significant. Claude grew 64x over the 19-month period and overtook Perplexity in March 2026. Gemini is the quiet #2, growing 3.2x with low volatility. Perplexity peaked in March 2025 and has since declined 61%. Copilot collapsed 96% from peak. For marketers optimizing "AI visibility" as a category, this data suggests most referral value concentrates in a single platform — and the second-place finisher is not who most strategies assumed.

Ahrefs' analysis of 863,000 keywords found that pages cited in Google AI Overviews now rank in the top 10 for the same query only 38% of the time - down from 76% seven months earlier. The drop coincides with Google's January 2026 rollout of Gemini 3 as the default AI Overview model, which replaced 42% of previously cited domains and introduced broader query fan-out. For SEO teams whose GEO strategy assumes ranking well leads to AI citation, the 38% figure means that assumption now fails the majority of the time.

"The Previsible report is the most important data point in this issue. 92.4% of AI referral traffic from a single platform changes the optimization calculus completely. But the Claude 64x growth number is the one to watch - Claude is now ahead of Perplexity in referral sessions, and it's the platform most GEO strategies still treat as a footnote. The 80% figure from Brand Auditors is equally important: if 80% of AI-cited URLs don't rank in Google's top 100, then SEO rankings and AI citation are nearly independent variables. You need a separate measurement framework for each. Running only one while assuming it predicts the other is the most common GEO mistake I see right now."