AI Answers in Four Industries: Where ChatGPT and Google Get Their Sources

In every industry, ChatGPT and Google mostly did not cite the same sources, and worked from two different reading lists. A follow-up in October 2026 checked ChatGPT against Bing as well: where both engines could be checked, most of what it pulled up was on neither engine's first page.

The pattern from our software teardowns holds outside software. Google's AI Overviews lean on the sites Google already ranks: 59% of the source links in the Overviews we could check came from domains in the organic top ten for the same search. ChatGPT's citations overlapped with that top ten far less, and with the Overview itself less still. Two reading lists mean two sets of sources to earn, which is why our AI search optimization services measure Google and ChatGPT side by side.

Read the columns as shares of source links (Overviews) and of cited sites (ChatGPT), counted once per answer. The Overview link share counts the 60 Overviews, of the 86 with readable sources, that came from Google pages that passed the swap check described in the method.

ChatGPT and Google's AI Overviews each cite a different set of sources in each industry.

Fintech: ChatGPT relied on personal finance publishers and regulators. NerdWallet was cited in 9 answers and the Consumer Financial Protection Bureau's consumerfinance.gov in 8.

Healthcare: ChatGPT spread its citations thinly and leaned on government sources: 17 of its 52 cited sites were .gov health sites or the UK's NHS. No single hospital or directory dominated.

Legal: the American Bar Association (americanbar.org) was ChatGPT's most-cited source, followed by legal directories and online legal services. Google's results and Overviews leaned on the same directories plus Reddit and Quora.

Ecommerce: ChatGPT cited product testing publishers (RTINGS, WIRED, Tom's Guide). Google's Overviews linked to Google's own product listings in 21 of 25 answers, so for product questions Google's shopping data is part of the answer itself.

Whichever sources your industry depends on, the agency you hire should be able to show its own data. Our list of top AI SEO agencies in 2026 checks 18 firms for published pricing, research and documented results.

Reddit ranked in Google's top ten for 64 of the 100 questions, and YouTube was linked in 55 of the 86 AI Overviews whose sources we could read. ChatGPT cited neither site in any of the 100 answers. That matches what we found on 700 software questions (Reddit, YouTube).

We collected the data for all four industries from Google and ChatGPT on the same day.

Questions: 25 per industry, written in the words a customer would use: "best" questions, how-to-choose questions and cost questions. Fintech covers consumer and small business money products, healthcare covers patients choosing care, legal covers people choosing a lawyer or legal service, ecommerce covers consumer product purchases. The full list is in the dataset.

Google: desktop results, United States, English, via the DataForSEO SERP API, collected on September 26, 2026 (timestamps in the files are UTC). Some AI Overviews load after the page; for those 37 questions we re-ran the same search the same evening with the Overview loaded and took its sources and top ten from that run. For 7 questions the Overview did not appear in the re-run, so their sources are missing; they still count as "Overview shown". Corrected October 23, 2026: 28 of the 100 pages came back swapped, with fewer than half of their sites on Google's page for the same question on October 23, so for those 28 questions the top ten is now the October 23 page (DataForSEO, Web results only). Those pages carry no AI Overview, so the Overview link share counts only Overviews from pages that passed the same check (60 of 86); the other Overview figures are as collected on September 26 and include the swapped pages.

ChatGPT: web search on, logged out, United States, English, one run per question, via the DataForSEO ChatGPT scraper, same evening. One healthcare question returned no answer on the first run and was run once more.

Limits: 25 questions per industry is a snapshot, not a census. One run, one country, desktop only. Local questions ("best divorce lawyer") were asked without a city, so results reflect national rather than local answers. Treat the figures as directions, not constants.

You can check the figures in this note against the 100-question, four-industry dataset in the four files below.

• queries.csv (100 questions)
• per-question.csv (Google top ten, Overview sources and ChatGPT cited domains for each question)
• chatgpt-citations.csv (every ChatGPT citation with its URL)
• google-control.csv (the Google top ten used for each question, and for the 28 whose September 26 page came back swapped, that page beside the October 23 page that replaced it; added October 23, 2026)

Released under CC BY 4.0. Industry pages: fintech, healthcare, law firms, ecommerce.

Every industry draws on a different mix of sources, so it is worth seeing which ones ChatGPT and Google cite in yours. The Category Salience Brief maps them across Google and the AI surfaces, with competitors side by side.