Study of 278,499 visible citations finds a narrow cross-platform source group for high-stakes money and health decisions, despite 88 domains remaining in the monthly Top 100.
SAN DIEGO, Oct 5th, 2026. Only 15 websites reached the Top 100 cited sources on all six artificial intelligence platforms in a high-stakes consumer-decision study released by LLM Authority Index. The analysis covered 278,499 visible citation events from 60,881 deduplicated responses collected from July through September 2026.
The 2026 AI Citation Authority Study: Which Websites Does AI Cite for High-Stakes Decisions? examined Google AI Overviews, Google AI Mode, ChatGPT, Gemini, Perplexity and Microsoft Copilot across 53 source vertical datasets covering financial services, insurance, healthcare products and providers.
The six platform-specific Top 100 lists contained 246 distinct domains. Only 15 appeared in every list; 117 appeared in just one. Meanwhile, 88 domains remained in the aggregate monthly Top 100 across July, August and September. Reaching every Top 100 is a higher threshold than simply being cited by every platform.
NerdWallet led the pooled ranking, followed by Forbes, CNBC, Reddit and Bankrate. Yet NerdWallet was not among the 15 domains reaching every platform’s Top 100. Wikipedia did not appear in the pooled Top 25. These rankings reflect a finance-oriented sample with heavier Google coverage, not all AI searches.
“The No. 1 website overall was not in the Top 100 on every platform,” said Mark Huntley, founder of LLM Authority Index. “For a marketing team, that is the difference between a headline ranking and a useful media plan. Start with the decision the customer is making, then check the sources each platform actually cites.”
The 15 qualifying websites were Amazon, Bankrate, Business Insider, Credible, Experian, Finder, Forbes, GoodRx, Healthline, HearingTracker, LendingTree, Money.com, SeniorLiving.org, Squaremouth and StockBrokers.com. The group spans publishers, marketplaces and specialist resources, including hearing-aid reviews, senior-care comparisons and travel insurance. These are source-visibility findings, not endorsements of the listed companies or their products.
Category differences were also substantial. The leading 100 sources accounted for 74.8% of domain-response appearances in credit, debt, banking and lending, compared with 44.9% in health and medical decisions. This measure counts each domain once per response, regardless of how many of its pages were cited. Each category uses its own Top 100 and source-appearance total.
The report calls the difference between monthly source-set similarity and cross-platform similarity the Persistence-Portability Gap for AI citation source sets. Using the same overlap measure, median similarity was 85.2% across aggregate monthly Top 100 lists and 36.1% across platform Top 100 lists, a gap of approximately 49.1 percentage points. These are pooled comparisons, not predictions of future visibility.
For chief marketing officers and publishers, the findings support category- and platform-specific source research rather than one universal outreach list. Citation visibility should be assessed separately from whether an AI system recommends a particular brand.
The study is observational and measures visible citations, not hidden retrieval, source accuracy or whether a publisher causes a brand recommendation. Platform sampling volumes differed, some verticals lacked July data and source datasets overlapped.
Read the full study, including source tables, methodology and limitations: The 2026 AI Citation Authority Study: Which Websites Does AI Cite for High-Stakes Decisions?
About LLM Authority Index
LLM Authority Index provides AI market intelligence, citation research, company and competitor reports, and ongoing visibility monitoring. Brands and publishers seeking analysis of their own citation sources and competitive AI visibility can contact the team to discuss a tailored assessment. Affiliated businesses may have commercial relationships with sources in the study; those relationships are not ranking inputs.
Media Contact
Founder, LLM Authority Index
Email: mark@citeworksstudio.com
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Website: llmauthorityindex.com
