The Sites AI Trusts Across Topics — and What Brands Can Learn From Them

Key Findings

• The websites AI cites across the most topics are PubMed Central, NerdWallet, Bankrate, and LegalClarity. In Stacker's analysis of more than 3.9 million citations across six AI platforms, each appeared among the top 10 most-cited sources in four different topic areas.
• AI prefers to cite content built on original data and deep expertise. The most widely cited sources published peer-reviewed research, proprietary data, or specialized coverage of a particular topic area like personal finance.
• AI cites brand content more often than journalism. Brand sites appeared in 29% of tracked AI responses, compared with 21% for editorial sites. The brands that won the most citations created practical content using their own data.

Citations — the links included in an LLM's responses — are like the front page of AI search. They’re how AI platforms like ChatGPT, Claude, and Gemini show the sources they consider trustworthy enough to inform their responses. For brands, earning a citation means making your brand visible in the very moment a user is asking a relevant question.

We recently analyzed more than 3.9 million citations from across six AI platforms to create Stacker's 2026 AI Trust Report, to understand which sources LLMs trust most and what brands can do to become one of them.

We found that the mix of most-trusted domains varied according to the topic area. For example, while AI platforms tended to cite sources like credit bureaus and personal finance editorial for questions related to managing your money, they cited peer-reviewed research and drug pricing brands for health-related queries.

Overall, we found that AI treats brand content as at least as trustworthy as journalism: Brand sites were cited in 29% of the responses we tracked, while editorial sites were cited in 21%.

But there were some sites that were deemed trustworthy by AI in more topic areas than others. These sites demonstrated deep expertise in a particular area, publishing original data and research with practical implications for many parts of everyday life.

Across all six platforms, the domains that were cited in the most topic areas were PubMed Central, NerdWallet, Bankrate, and LegalClarity. Experian, which publishes consumer-friendly articles covering personal finance, was also frequently cited in a variety of topic areas.

Sites that were trusted in the most topic areas

Here's a look at the domains whose trustworthiness transcended verticals.

Showing up across verticals means that LLMs view these domains as authoritative even on topics that are outside their core focus area. For a brand, understanding why these domains are widely cited could mean showing up even for prompts that are only tangentially related to your product.

AI search engines don't cite just one type of website — they pull from academic research databases, editorial publications, government sources, and brand content.

Peer-reviewed research was among the most widely trusted sources in our analysis. The "pmc.ncbi.nlm.nih.gov" domain is the National Institutes of Health's PubMed Central, the free archive of biomedical and life sciences research. It was a top-cited source in prompts related to health, business, science, and lifestyle.

Meanwhile, we found that specialized editorial showed up in more topic areas than general news. For example, NerdWallet and Bankrate were both top-cited sources despite having a relatively narrow focus area. The specific expertise they offer clearly holds value for LLMs looking for authoritative sources to cite.

Brands dominated the top 10 lists of individual verticals (see the AI Trust Report for more), but Experian was the lone brand to appear in the top 10 list of three or more verticals. It was a top-ranked brand in the Personal Finance, Transportation, and Travel categories. Experian publishes a lot of content that heavily features its own data, and as a credit bureau, it could be relevant to anything related to personal finances, whether that’s budgeting, buying a car, or planning a trip.

Our research found that brands that harness their proprietary data to create helpful content overwhelmingly won citations over their peers. Other examples included GoodRx, which performed well in the Health category, and Realtor.com, which won real-estate-related citations.

Takeaways for brand content teams

What does this mean for brands looking to use their content to build AI visibility? A few things:

• Go deep, not broad. The sites that were trusted across the most verticals — like NerdWallet, Bankrate, and Experian — built deep expertise in one subject area. Own the subject your brand knows best rather than trying to cover everything.

• Lean into data that only your brand can produce. The most-cited brands published findings drawn from their own data rather than summarizing others' work.

• Get your content onto domains that AI already trusts. Strong owned content earns citations, but so does content placed on established publications. Expanding the surface area where LLMs can encounter your brand increases the likelihood that it will be cited by AI. A Stacker study published in December 2025 found that brand stories distributed across the Stacker network saw their AI citations grow by up to 325% compared to their pre-distribution baseline.

As consumers continue to turn to AI for answers, the brands that win will be the ones that can create content that's worth citing — and make sure it shows up in the places that AI trusts.

Methodology

Stacker's analysis looked at citations from across six AI platforms: ChatGPT, Claude, Google AI Mode, Google AI Overviews, Google Gemini, and Perplexity. The analysis was based on prompts that Stacker tracked via the AI visibility platform Scrunch between May and August 2026. Because these prompts were tracked on behalf of Stacker's clients, they tended to skew towards personal finance and health topics.

Our analysis looked at the 10 Stacker-defined story categories with enough GEO data to draw conclusions. To zero in on the websites that earned trust across the board, we looked at the domains that appeared in the top 10 most-cited list across the greatest number of verticals.

Download the 2026 AI Trust Report to see the top 10 sources for each story category, how citations varied by platform, and the trends that held true across every vertical we studied.