66% of the sources ChatGPT, Gemini, Perplexity and Google's AI features cite in their answers are .com websites, against 14% for government (.gov) and university (.edu) websites. ChatGPT is the one AI engine that cites government and university websites more often than .com.
Analysis of 155,312 cited URLs · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Key Findings
- 1.66.1% of citations in AI answers go to .com websites, five times the share of the next most-cited domain ending, .org, at 12.9%.
- 2.40.8% of ChatGPT citations go to government (.gov) and university (.edu) websites, more than its 34.7% for .com websites and over three times the rate of Perplexity, Gemini or Google's AI features.
- 3.Google AI Mode cites .com websites 74.9% of the time and Google AI Overviews 74.5%, more than double ChatGPT's 34.7%.
- 4.In AI answers about taxes, 39.6% of citations go to government and university websites, against 0.4% in AI answers about shopping.
- 5.The UK's .uk is the most-cited country domain in AI answers to US questions, at 1.85% of all AI citations, ahead of Australia's .au (0.62%) and Canada's .ca (0.48%).
Summary
Ask an AI engine how to file a tax extension and about four in ten of the sources listed under its answer come from government agencies and universities. Ask it which laptop to buy and nearly nine in ten sources are companies, retailers or publishers on a .com address. The sources an AI engine picks change with the question, and they change even more with the engine.
Those sources matter because a citation is the link an AI answer shows next to its claims, and it is one of the few ways an AI answer sends a reader to a website. Knowing what kind of site wins citations tells a business who it is really competing with: other companies, or official bodies that are the primary authority on the topic.
Across all five engines, 66.1% of citations point to .com websites, about two in every three. Government and university sites together take 14%, about one in seven. ChatGPT reverses that pattern: 40.8% of its citations are .gov or .edu pages and 34.7% are .com.
What we measured
On September 23, 2026 we asked 2,984 general questions, on topics from taxes and health to shopping and software, to five AI engines: ChatGPT, Gemini, Perplexity, Google AI Mode and Google AI Overviews (the AI summary that appears above Google's search results). Every question was asked from a US location. We collected every web page cited in the answers, 155,312 in all, and grouped them by engine and by the topic of the question.
A citation is a source link an AI engine shows with its answer. The domain ending, or top-level domain, is the last part of a web address: the .com in example.com. A .gov address belongs to a government body, .edu to a college or university, and .org is the ending most nonprofits use. Two-letter endings such as .uk and .ca belong to countries. Every share in this study is a share of citations, so a site cited ten times counts ten times.
Two thirds of AI citations go to .com websites
The .com ending is where most of the commercial web lives: companies, retailers, news and magazine publishers, review sites and forums. Its 66.1% share shows that for everyday questions, AI engines mostly answer from the same kinds of sites people find in ordinary search. The nonprofit .org ending comes a distant second at 12.9%, followed by .gov at 9.8% and .edu at 4.3%.
Source: Suff Digital analysis of 155,312 cited URLs · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Foreign websites show up in answers to US questions. The UK's .uk is the most-cited country ending at 1.85% of citations, almost three times the share of .net (0.65%), followed by Australia's .au (0.62%) and Canada's .ca (0.48%). These are English-speaking countries whose public bodies and publishers write about the same everyday topics, so their pages compete with American ones. The .int ending, used by international organizations, takes 0.29%, and the tech-startup endings .ai and .io take 0.24% each.
ChatGPT cites government sites as often as .com sites
ChatGPT is the outlier. 34.7% of its citations go to .com websites, about half the rate of any other engine, while 40.8% go to .gov and .edu. Government sites alone take 35.3% of ChatGPT's citations, slightly more than .com, and .org takes most of the rest. Its list of sources reads more like a research bibliography than a page of search results.
Source: Suff Digital analysis of 155,312 cited URLs · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
| Engine | .com | .gov + .edu |
|---|---|---|
| ChatGPT | 34.7% | 40.8% |
| Perplexity | 65.4% | 12.7% |
| Gemini | 72.4% | 6.6% |
| Google AI Overviews | 74.5% | 8.7% |
| Google AI Mode | 74.9% | 8.6% |
The gap to the other engines is wide. ChatGPT's government and university share is more than three times Perplexity's 12.7% and six times Gemini's 6.6%. For a business, this means the same question can put you up against different competition depending on the engine: on ChatGPT, a company page is weighed against official guidance from agencies and universities far more often than anywhere else.
Google's AI features cite .com sites three times out of four
Google's AI products lean hardest on the commercial web. Google AI Mode cites .com websites 74.9% of the time, Google AI Overviews 74.5% and Gemini 72.4%, more than double ChatGPT's 34.7%. Government and university sites get 8.6%, 8.7% and 6.6% of their citations respectively.
Google's AI features sit on top of Google Search, and their sources look like a page of Google results: companies, publishers and review sites, with official sources in a supporting role. Perplexity falls between the two styles, with 65.4% of citations on .com and 12.7% on .gov and .edu. If your customers get their answers from Google, the sites you are competing with for a citation are mostly other companies and publishers, the same ones you already compete with in search.
The topic decides whether official sources get cited
Across all engines, the share of citations going to government and university websites rises and falls with the subject of the question. It peaks in taxes at 39.6%, then weather at 34.2%, health at 31.8% and education at 28%. These are subjects where a government agency or a university is the primary authority: tax rules, weather forecasts, public health guidance and admissions.
Source: Suff Digital analysis of 155,312 cited URLs · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Commercial topics look completely different. In shopping, tech and software answers, government and university sites take under 2% of citations, and .com sites take 85% to 89%. A tax question is roughly 100 times more likely than a shopping question to send a citation to a government or university site, so the kind of business you run largely decides whether official sources are part of your competition at all.
What this means for businesses
Do not change your domain for AI. Nothing here suggests a different ending would help; the ending mostly reflects the kind of organization behind a site, and .com sites already win two thirds of all citations. The useful question is who you are competing with, and that depends on your topic and on the engines your customers use.
If you sell products, software or services, your competition for citations is other companies and publishers, especially in Google's AI features, where three in four citations go to .com sites. Win those with pages that answer buying questions directly: clear specifications, prices, comparisons and evidence from real customers. If you work in taxes, health or education, your pages are cited alongside official sources, particularly on ChatGPT. Cite the official guidance on your pages and build on it with practical steps, worked examples and local detail.
Then check where you stand. Ask the questions your customers ask in ChatGPT, Gemini, Perplexity and Google, and note which sites each engine cites. Working with an ai seo company that tracks those citations across engines shows you exactly which sources your pages sit next to.
Embed this research
Paste this on your site to embed the charts. It links back to the source automatically.
<iframe id="sd-ai-citations-by-domain-extension" src="https://www.suffdigital.com/embed/data-studies/ai-citations-by-domain-extension" width="100%" height="600" style="width:100%;border:1px solid #E5E7EB;border-radius:12px" loading="lazy" title="AI Answers Cite .com Websites 66% of the Time vs 14% for Government and University Sites - Suff Digital"></iframe>
<script>window.addEventListener("message",function(e){if(e&&e.data&&e.data.sdEmbed==="ai-citations-by-domain-extension"&&e.data.height){var f=document.getElementById("sd-ai-citations-by-domain-extension");if(f){f.style.height=e.data.height+"px";}}});</script>
<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.suffdigital.com/resources/data-studies/ai-citations-by-domain-extension">AI Answers Cite .com Websites 66% of the Time vs 14% for Government and University Sites - Suff Digital</a></p>
Cite this study
Suff Digital. (2026). AI Answers Cite .com Websites 66% of the Time vs 14% for Government and University Sites. https://www.suffdigital.com/resources/data-studies/ai-citations-by-domain-extension
AI Answers Cite .com Websites 66% of the Time vs 14% for Government and University Sites - Suff Digital - https://www.suffdigital.com/resources/data-studies/ai-citations-by-domain-extension
Frequently asked questions
Related studies
- AI SEOPerplexity Cites a Foreign Website in 49.3% of Answers to US Questions vs 5.5% for ChatGPT
- AI SEOThe Most Academic AI: Perplexity Cites Universities and Government Sites in 58% of Answers
- AI SEO44.9% of the Websites AI Engines Cite Are Small, Low-Authority Sites
- AI SEOOld Domains Win AI Search: Websites Over 20 Years Old Collect 79.8% of AI Citations