AI Visibility Index: What three months of data reveals by Semrush Enterprise

AI search evolves every month. This constant flux is reshaping which brands get visibility and which sources AI models trust most.

We now have three months of data in the AI Visibility Index, tracking ChatGPT and Google AI Mode.

The key takeaway: AI search is volatile. This is likely to be normal for the immediate future.

The brands that win are monitoring and adapting to these changes in real-time.

The research tracks 2,500 real-world prompts across five key verticals: Business & Professional Services, Digital Technology & Software, Consumer Electronics, Fashion & Apparel, and Finance. revealing seismic shifts in source diversity, brand mentions, and model behavior that no marketer can afford to ignore.

What changed at a model level?

• ChatGPT: Unique brand mentions fluctuated. Meanwhile, sources cited by ChatGPT surged 80% in October alone – a fundamental shift toward greater source diversity.
• Google AI Mode: Brand mentions dropped 4% from August to October, suggesting tighter controls on recommendations. Source diversity increased more moderately at 13%, indicating a more conservative approach than ChatGPT.

Key trends over three months

Reddit’s correction and resurgence: ChatGPT reduced Reddit citations by 82% between August and October. However, it remains the fourth most-cited source in ChatGPT. During the same period, Google AI Mode increased Reddit usage by 75%, making it the second most-used source. The platforms are converging on Reddit’s value, just from opposite directions.

Brand diversity varies by vertical and model: In ChatGPT, Consumer Electronics saw a 20% increase in unique brands mentioned, while Finance dropped 15%. Google AI Mode showed universal declines across almost every vertical. More proof that each model requires its own approach.

Top brands remain relatively stable: Among the top 100 brands, there were 25 new entrants over three months—but only two broke into the top 50. For leading brands, changes in visibility stayed within a ~20% range, much narrower than the broader market volatility.

Source strategies must be model-specific: ChatGPT and Google AI Mode agree on which brands to mention 67% of the time, but only 30% of the time on which sources to use. Wikipedia, Forbes, and Amazon dominate ChatGPT, while Amazon and YouTube lead in Google AI Mode.

The update confirms that AI visibility requires constant monitoring. Both platforms are experimenting with diversity, correcting for overreliance, and refining their approaches.

What this means for your strategy

In AI search, yesterday’s visibility doesn’t guarantee tomorrow’s.

Sixty-one of the top 100 brands appear in both ChatGPT and Google AI Mode’s results, showing high brand similarity. But source similarity is much lower and actually decreased from August to October.

Translation: build your brand visibility across both platforms, but tailor your source strategy to each model individually.

Explore the AI Visibility Index to discover the complete rankings, interactive leaderboards, and deeper trends across all five industries. Then download the proven tactics to build visibility in this rapidly evolving landscape. All for free.