When AI cites a guarantee, two in three belong to national networks

Short answer: when ChatGPT or Gemini recommend a business, they almost never mention a guarantee: 63 passages out of 16,022 across four countries, 0.4%. And two times in three, the guarantee they repeat belongs to a national network: Midas, AAMCO, Benjamin Franklin Plumbing, Lockforce, Bosch Car Service. All 63 are in car repair, home repair and driving schools. For lawyers, accountants, hotels, restaurants and every other trade we measured, the count is zero, out of 11,213 passages.

An AI answer repeats a guarantee the way it repeats a brand: the national networks first.

What was measured

Our four studies, re-read on October 4, 2026: the same buyer questions ("the best auto repair shops in Houston", "a good locksmith in Cardiff") put to ChatGPT (gpt-4o-mini) and Gemini through their APIs, without web search, in the United States (collected September 13, 2026), the United Kingdom (July 31), France (July 30) and Brazil (August 6). 3,600 answers, cut into passages; we kept the 16,022 that name a business, with the same cleaning as our recent editions. In each, we looked for a guarantee offered by the business, in English, French and Portuguese: "satisfaction guarantee", "warranty on parts and labor", "12-month guarantee", "garantie décennale", "oferece garantia". A guarantee denied or left impersonal ("past success doesn't guarantee future performance") did not count, nor did advice ("ask about warranties"). The detector was tested on 14 phrasings it must catch and 8 it must not. Then we read every passage it kept, 77 of them, and removed 14: advice and criteria lists, a services platform, names that stand for several firms, a placeholder name, shopping-centre kiosks rather than businesses, and one figure of speech. 63 remain.

Car and home repair: the only trades where a guarantee comes up

Every one of the 63 guarantees is in a trade where something gets fixed. Car repair leads, with 21 of its 1,011 passages (2.1%); home repair follows, plumbers, electricians, heating and air conditioning, locksmiths and gas engineers, with 40 of 2,816 (1.4%). Driving schools add two passages, both for the AA's money-back guarantee in the United Kingdom. In 11,213 passages about lawyers, accountants, insurance brokers, estate agents, dentists, hotels, restaurants, bakeries, salons, photographers and agencies, not one guarantee. Among single trades, American auto repair shops carry the most, 11, then Brazilian garages (8) and Brazilian air-conditioning companies (7).

Two in three belong to a national network

Of the 63 guarantees, 41 belong to a national franchise or network, often said in so many words in the answer itself: "a major national franchise", "part of a national network", "uma rede nacional". Benjamin Franklin Plumbing appears four times in ChatGPT's answers, in New York, Los Angeles and Philadelphia, each time with its satisfaction guarantee; Midas four times; AAMCO twice, both times for its "nationwide warranty"; Lockforce four times in British cities, twice "backed by a national guarantee"; Bosch Car Service garages five times in Brazil. The 22 others are businesses of one city or region, and when the answer cites them, the guarantee often has a name or a term of its own: a "no-hassle" guarantee for a Denver plumber, a "No-Lemon" guarantee for an Austin heating company, "a 3-year/36,000-mile warranty on most repairs" for a San Diego garage. In the United States, 14 of ChatGPT's 20 guarantees belong to franchises, against 1 of Gemini's 7: the same lean we found in who gets named at all (ChatGPT leans to chains, Gemini to independents).

Google stopped guaranteeing, too

On the paid side of local search, the platform's own guarantee is gone. Google has discontinued the money-back guarantee attached to its "Google Guaranteed" badge in Local Services Ads, the paid listings for tradespeople: its Local Services help page, read on October 4, 2026, says so, and reimbursement requests were accepted only for services booked before December 7, 2025. According to the announcement sent to advertisers, relayed on Google's Business Profile community, the badge has read "Google Verified" since October 20, 2025: it says a business went through Google's screening, no longer that Google will pay if the job goes wrong. The guarantee a customer can still read is the one the business writes itself, and the assistants rarely repeat even that.

What it means if you are the business

If you repair cars or homes, a guarantee is one of the reasons the assistant can give for naming you, but it reaches the answer rarely, and mostly when a national brand stands behind it. A national network writes the same guarantee, in the same words, on every branch page, every listing and every van; that is a reasonable reading of why its guarantee travels, not something we measured. An independent can do the same at its own scale: give the guarantee a name, a term and a scope ("12 months on parts and labour", "we come back free if the leak returns within 90 days"), and write it identically on your site, your map listing, your quotes and the directories that list you. "Satisfaction guaranteed" on its own is what everyone says, and it gives an engine nothing to tell you apart with, as we saw with prices (AI praises a clear price more than a low one). If you are a lawyer, an accountant or a hotel, a guarantee is not what the answer is made of. Nothing here guarantees being named.

What this does not prove

• These are the models' answers through their APIs, without web search: the way our audit asks. Consumer apps with search switched on may show ads and listings with their own badges, which this measurement does not see.
• Four studies collected between July 30 and September 13, 2026, one pass per question. The models have moved since, and nothing here measures that drift.
• 63 is a small base: the split by country, engine and trade is an order of magnitude, not a precise share.
• A vocabulary misses guarantees phrased otherwise, so the count is a floor. The 77 passages it kept were read one by one; the 14 removed are listed, each with its reason, in our measurement files.
• A business counts as a national network when the answer says so or when it is a known franchise. We did not check that each guarantee cited still exists, nor that it is what made the assistant name the business.