Semrush's newest AI Visibility Index found Google's AI Overviews share the fewest top brands with ChatGPT, Gemini and AI Mode, which is outside support for checking AI Overviews on their own.

In March Google said AI Mode would carry no ads for people who connect their Gmail and Photos ("Personal Intelligence"). On Friday it told Search Engine Land it is starting to test ads for exactly those users. Google's help page now says ads "will not be based directly on your Gmail inbox or your Google Photos library", but that the summaries and inferences Search draws from them "may be used to show you ads". The same page says AI Mode can use those apps "to provide responses that are specific to you", with past restaurant bookings shaping new restaurant recommendations as its example. The feature is opt-in, for signed-in personal accounts aged 18 and over.

ChatGPT's newest notes are 16 October (Slides, GPT-6 Pro) and 15 October (a new voice model that "uses a wider range of short phrases to let you know when it's searching"), with nothing on citations, links or shopping. Google's changelog still ends at 16 October and the status dashboard shows no incident since the September spam update. Perplexity's newest entry drops several older models from the Agent API list and adds GPT-6 Astra and DeepSeek V4 Pro, still naming no Sonar model. Anthropic's newest post (18 October) is about a public benefit fund. Bing's webmaster blog has nothing since 13 October.

Method in one clause: fixed monthly sets of 2.5 million UK and 25 million US prompts built from Semrush search data, run on ChatGPT, Gemini and Google AI Mode from January to July 2026, plus a separate AI Overviews dataset from real keywords, averaged across 22 categories. Any two platforms shared 63 to 70 of their top 100 mentioned brands in the UK and 70 to 78 in the US. AI Overviews had the lowest brand overlap with the other three in every month, and AI Overviews and ChatGPT had the lowest source overlap of any pair in both markets (no number given). Only 24 UK and 36 US domains made the top 100 on all four platforms every month. Fewer than half of the top 100 mentioned brands were also top 100 cited domains (36.7 to 45.3 of 100 in the UK). In AI Mode the top 10 sources took 23.2% to 35.8% of UK citations, against 12.8% to 15.4% for ChatGPT.

Limits: a vendor press release, not the full report; Semrush sells an AI visibility product; big consumer brands, not coaches or local services; no Claude or Perplexity; the overlap figure for AI Overviews is stated without a number.