Perplexity Cites a Foreign Website in 49.3% of Answers to US Questions vs 5.5% for ChatGPT

An American asks an AI engine how much sleep a teenager needs, or how to prune roses. The answer reads smoothly, and the sources underneath include Britain's National Health Service and the Royal Horticultural Society. The advice may well be sound, but it was written for readers in another country.

That matters for US businesses and publishers in two ways. First, the competition for a citation is not only American: on many everyday topics, a US page is weighed against authoritative foreign sources. Second, on country-specific subjects such as medical guidance, regulations, prices or product availability, a US reader may need a source written for the US, which leaves room for a clear US page to win.

Across five AI engines, 14% of answers to questions asked from the US cite at least one foreign website. Perplexity does so in 49.3% of its answers and ChatGPT in 5.5%. On fitness, sleep, pets and gardening questions, more than one answer in five cites a foreign source; on insurance and tax questions, fewer than one in twenty-five.

On September 23, 2026 we asked 2,984 general questions, on topics from fitness and gardening to taxes and insurance, 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, producing 25,940 answers, and we recorded every website each answer cited.

A cited website counts as foreign when its address ends in another country's two-letter code, such as .uk for Britain, .au for Australia or .ca for Canada. Codes that are widely used as generic web addresses, such as .io, .co, .ai, .me and .tv, do not count as foreign. Answer shares count an answer once if it cites any foreign site; citation counts count every foreign link.

Perplexity is by far the most international engine. Nearly half its answers to US questions cite a foreign site, more than three times Google AI Overviews (15.4%) and nine times ChatGPT (5.5%). Perplexity lists about 20 sources per answer, which gives it far more chances to include one from abroad.

ChatGPT stays closest to home. It cites fewer sources per answer and leans on US government and university sites, so a foreign source appears in about one ChatGPT answer in twenty. For a US business, that means the engine your customers use changes who you compete with: on Perplexity, a British or Australian guide is a real rival for the citation.

Foreign websites receive 4.1% of all citations in answers to US questions. Britain dominates that group: .uk websites received 2,866 citations, three times Australia's 962 and well ahead of Canada's 749. All three are English-speaking countries whose governments, health services and publishers write about the same everyday topics Americans ask about.

Language is the common thread. AI engines answering in English draw on the whole English-language web, and national health services, public broadcasters and government advice sites in these countries publish some of the clearest, most thorough guidance available on health, home and lifestyle questions.

The foreign sources AI engines cite most are public and media institutions. The NHS leads with 365 citations, followed by the BBC with 336 and the Royal Horticultural Society with 138. Canada's government portal, an Australian state health site and the European Union's portal follow.

These are trusted, well-written sources, and that is exactly why they compete with US pages. A US health publisher, garden center or financial adviser is not up against an obscure foreign blog; it is up against a national institution with decades of authority.

The topic decides how often an answer crosses the border. Foreign sources appear in 26.5% of fitness answers, 26% of sleep answers, 23.3% of pets answers, 22.3% of beauty answers, 21.5% of gardening answers and 21.4% of mental health answers. These subjects work much the same everywhere, so a British or Australian guide answers a US question well enough.

Where the rules are national, AI engines stay home. Insurance (3.1%), taxes (3.8%), real estate (3.9%) and mortgages (5.5%) rarely cite a foreign site, because a British tax rule or an Australian mortgage product does not answer an American question.

If you work in health, fitness, gardening, pets or lifestyle, your competition in AI answers includes the NHS, the BBC and Australian government sites. Those sources are authoritative, but they are written for UK, Australian or Canadian readers, so units, prices and rules can differ for a US reader. A page that states clearly who it applies to, with US units, prices, regulations, product availability and US sources, gives an AI engine a better local option.

Check how AI engines answer your core questions from a US location, especially on Perplexity and Google AI Overviews. If foreign sources appear, publish the US-specific version they are missing, and say in the first lines that it is written for US readers.

Working with an ai seo company like Suff Digital helps US brands find the questions where foreign sources are winning citations and build the pages to replace them.

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