Topical Authority Matters in AI Search, Study Finds

Topical authority remains a significant factor for brand visibility in AI-driven search, according to a recent study by Semrush. The research, which analyzed data from January to June 2026, suggests that AI search engines, like ChatGPT, tend to assign "topic ownership" to brands that consistently demonstrate expertise within specific categories. This means that establishing a strong presence and authority around core topics is essential for long-term durability in AI search results, even as AI models become more sophisticated in answering queries directly.

The study utilized the Semrush AI Visibility Toolkit, examining 1,094 US categories with five prompts per category. Over the six-month period, the analysis covered more than 220,000 domains, 50,000 brands, 600,000 citations, and 220,000 URLs. The methodology focused on tracking which brands ChatGPT mentioned most frequently across these prompts, aiming to understand how AI models attribute authority. The findings indicate that once a brand secures a substantial share of mentions within a particular topic, it is likely to maintain that position.

This contrasts with the evolving landscape of AI search, where generative models can provide direct answers, potentially reducing click-through rates to websites. However, the Semrush study implies that the underlying principle of topical authority still holds. For businesses, this means that content strategies should prioritize building deep expertise in their niche rather than pursuing broad, high-volume topics. For instance, a payroll software company should focus on detailed content about payroll taxes, deadlines, and regulations, rather than general finance topics. This approach aims to position the brand as a consistent and trusted source when users ask related questions, ultimately influencing future purchase decisions.

It is important to note the limitations of the study. The Semrush analysis did not measure sentiment, the quality of recommendations, user trust, or the impact on purchases. Furthermore, it did not track topic-level organic rankings. Despite these limitations, the core finding that topical authority influences AI search visibility provides a valuable insight for content creators and SEO professionals navigating the new era of artificial intelligence in search.