Organic search sessions across 54 advertisers tracked by Brainlabs fell 10.5% between January 2025 and April 2026, while referrals from ChatGPT, Gemini, Copilot and Perplexity rose 163% and converted at 1.5 times the organic rate, according to Google Analytics data the agency shared with Digiday.

The dataset spans 24 U.S. firms, 24 British brands and six clients in other markets across 19 sectors. Aggregate sessions dropped from 140.1 million to 125.4 million, and 46 of the 54 clients recorded declines. AI-driven key events, the Google Analytics label for purchases and sign-ups, climbed 335%.

The inflection came in September 2025, when Google AI Overviews began appearing on at least 30% of U.S. search results pages. Sam Paez, senior manager of SEO at Brainlabs, attributes the slide to “educational, informative discovery keywords” being intercepted upstream, before a click ever reaches a publisher. What remains is a smaller pool of visitors who’ve already worked through the discovery phase inside the model.

Sector variance is sharp. Retail, beauty and entertainment absorbed the smallest organic dips and the largest AI referral lifts. Fitness, fintech, insurance and CPG took the steepest hits, categories where buyers historically compared options across multiple tabs and now, apparently, don’t.

Paez also flags a measurement gap: when a user opens a fresh window after an AI answer, the visit logs as direct traffic, meaning AI’s actual contribution is understated.

That undercount is why the Interactive Advertising Bureau published its “Measuring Visibility in the AI Era” playbook on August 3, structured around a Presence, Prominence, Portrayal and Persuasion hierarchy, with a full attribution framework scheduled for November 12.

The channel that looks like it’s shrinking is quietly doing the qualifying work the front page of Google used to do.

Sources