Luxembourg Fiduciaire AI Visibility Index · Edition 1 · Published 10 November 2026
Which Luxembourg accounting firms do AI assistants name?
We asked the AI models behind ChatGPT, Gemini, Claude and Perplexity the questions a business owner asks when looking for an accountant in Luxembourg. Assistants answer differently every time, so one answer proves little. We asked every question five times, in three languages, on six model versions, and counted which firms the answers name.
Free and paid plans of the same assistant run on different models and give different answers. We queried the default model of each plan through the provider's official API:
- ChatGPT Freegpt-6-luna
- ChatGPT Plusgpt-6-sol
- Gemini FreeGemini 3.5 Flash-Lite
- Gemini AI Plus / ProGemini 3.8 Flash
- Claude, free and ProSonnet 5.5
- PerplexitySonar
How to read this index
- It measures one thing: how often AI assistants name a firm.
- It does not rate any firm. The figures say nothing about the quality of a firm's work, its prices or its service. A firm that is named rarely, or not at all, is not a weaker firm.
- "Best" and "top 10" are the askers' words. Some test questions use them because that is how people ask. They are not our judgement.
- Nobody paid. No firm paid to appear, and no firm can pay to change its figures.
Key findings
What the answers show
No firm is named in most answers.
The most-named firm, BDO, appears in 27 % of answers. The assistants named 161 verified firms in total, and 87 of them appear in fewer than 1 % of answers.
The assistant you ask changes which firms you hear.
About 80 % of the firm names given by the ChatGPT models and Perplexity are Luxembourg fiduciaires, and no Big Four firm appears in more than 3 % of the ChatGPT models' answers. The Gemini Plus / Pro model names BDO in 70 % of its answers, and 38 % of the firm names it gives are Luxembourg fiduciaires.
Five Luxembourg fiduciaires are named most often.
Financial Services Luxembourg (17.9 % of answers), Fiduciaire LPG (16.4 %), Atlas Fiduciaire (12.6 %), EasyBiz (11.2 %) and AS Comptabilité (8.9 %).
A firm's own website can be the source.
Atlas Fiduciaire's website is the second most-cited source overall (14 % of answers), after guichet.public.lu. The Gemini free-plan model cites it in 56 % of its answers and names Atlas in 46 %.
Some names could not be verified.
74 answers contained at least one firm name that we could not match to an existing firm in the public sources we checked. All 74 came from the Gemini models (68) and Claude (6). The Gemini Plus / Pro model answered about half the questions without a web search.
A new name takes time to appear.
One firm in the index changed its name in October 2025. A year later, 68 answers use the former name and 4 use the new one.
Share of answers
How often each firm is named
A firm's figure is the share of the 1,350 answers that name it. Each of the six model versions contributes 225 answers, so each counts equally. Firms are listed in order of that share. The order is not a quality rating.
161 verified firms were named at least once. We publish the 30 most-named firms, which include the 20 most-named Luxembourg fiduciaires. Further down, a figure rests on a handful of answers and can change from one run to the next, so we do not publish the full list. Any firm can ask for its own figures.
Is your firm one of the other 131?
131 more firms were named at least once in this edition. Ask us and we send your firm's figures, free: how often each assistant named you, in which language and for which questions.
Bars run from 0 to 30 %. Columns after "Named by" show the share of that model's 225 answers (or that language's 450 answers) naming the firm. "Named by" is how many of the six model versions named the firm at least once. Column names are the plan whose default model we queried through the API.
By assistant
Each assistant names a different set of firms
Of all the firm names each model gave, the share that are Luxembourg fiduciaires, international network firms and Big Four firms. The line under each bar shows the firms that model names most, with the share of its answers.
ChatGPT and Perplexity
Searched the web on every question. About four in five of the firm names they give are Luxembourg fiduciaires. No Big Four firm appears in more than 3 % of the ChatGPT models' answers, or in more than 7 % of Perplexity's.
Claude
Named 5.7 firms per answer. BDO and the Big Four are the firms it names most. On four French and German questions it did not search the web and explained how to choose an accountant without naming firms.
Gemini
The free-plan model cites Atlas Fiduciaire's website in 56 % of its answers. The Plus / Pro model answered about half the questions without a web search, named more than eight firms per answer, and named the large networks most.
Sources
The websites the answers cite
Share of answers citing each website. The government portal, a directory and the professional order sit next to firms' own sites. A listing on Editus or in the OEC directory is cited about as often as a firm's own website.
| Website | Type | Share of answers citing it |
|---|
Share of all 1,350 answers. Claude's web search attached no source citations to its answers, so for Claude only links written into the answer text count, and there are very few. Among the five other model versions the shares are about a fifth higher.
Verification
Names we could not verify
Before a name counts, we check that the firm exists: on its own website, in Editus, in the OEC member directory, in the business register or in the press.
The 74 answers came from the two Gemini models (68) and from Claude (6). None came from the ChatGPT models or Perplexity, which searched the web on every question. The Gemini Plus / Pro model answered about half the questions without a search.
Unclear names include a firm that has closed and names that only partly match an existing firm. The most frequent one appeared in 36 answers, almost all from the Gemini Plus / Pro model answering without a search.
We do not publish these names and do not count them in the table. A name we could not find may still belong to an existing firm, and we do not want to label a real firm as unknown. The list is available on request for research.
How the index was made
1,350 answers, not one
Type a question into an AI assistant and you get one answer out of many possible ones. Ask again and the list of firms changes. Even the most-named firm in this index is missing from 73 % of answers. A single screenshot says little, so we built the index in five steps.
We wrote the questions people ask.
15 questions a small business, a freelancer or a cross-border worker asks when looking for an accountant: setting up a SARL, VAT, payroll, a tax return, changing accountant. Each one in English, French and German.
We asked every question five times.
45 question versions, five runs each, on six model versions. That gives 225 answers per model and 1,350 in total. A firm's figure is a share of answers, so one lucky or unlucky answer changes little.
We kept the conditions the same.
Each provider's official API, with web search switched on and the location set to Luxembourg where the API allows it. No account history, no personalisation, no added instructions. Each model decided for itself whether to search.
We checked every name.
A name counts only if the firm can be found in public sources. 161 firms passed that check, with 6,377 mentions between them. 32 names did not pass and are left out.
We counted the same way for every firm.
A firm counts when an answer names it by its name, a known short name or its website. Being named as an example counts the same as being recommended first. Every model version has the same weight.
- Model versions
- The default model of each plan on 3 November 2026: ChatGPT Free (gpt-6-luna), ChatGPT Plus (gpt-6-sol), Gemini Free (Gemini 3.5 Flash-Lite), Gemini with a Google AI Plus or Pro plan (Gemini 3.8 Flash), Claude for free and Pro users (Sonnet 5.5), Perplexity (Sonar).
- Collection
- 4–5 November 2026, through each provider's official API. No screenshots and no scraping of the apps.
- Score
- Share of answers naming the firm: out of 1,350 overall, 225 per model version and 450 per language. German questions sometimes got answers in English or French. They count under German.
- Name list
- Letzscale collected every firm name that appears in the answers, with its known spellings and short names, and checked each one against public sources.
- Hand check
- A sample of 18 answers, three per model version, was read in full by hand and compared with the counts. One shortened firm name had been missed and was added. No firm was matched wrongly.
- Not covered
- Google AI Overviews (no official API), Microsoft Copilot and questions in Luxembourgish.
- Limits
- The figures describe these models, on these dates, with these questions. Assistants change often. What one person sees in the app can differ from the API, because the app adds that person's history and location.
- Next edition
- Repeats the same 15 questions, so firms can see how their figures move.
The 15 questions (English version)
- Which accounting firm would you recommend for a small business in Luxembourg?
- How do I choose an accountant in Luxembourg, and which firms are good?
- Top 10 fiduciaires in Luxembourg
- Which accounting firm can help me set up a SARL or SARL-S in Luxembourg?
- Who can handle VAT registration and VAT returns for my company in Luxembourg?
- Best payroll provider for a small company in Luxembourg
- Affordable accountant for a freelancer (self-employed) in Luxembourg
- Accountant in Luxembourg to do my tax return as a cross-border worker
- Best accountant for a tech startup in Luxembourg
- Who can do the bookkeeping for my small company in Luxembourg?
- I want to change my accountant in Luxembourg — which firm should I switch to?
- I'm starting a company in Luxembourg — which accountant should I contact first?
- Which accounting firms in Luxembourg have the best client reviews?
- Best accounting firm in Luxembourg City
- Accountant in Esch-sur-Alzette
For fiduciaires
What a firm can take from this
Your website is a source. The five most-named Luxembourg fiduciaires all have their own website among the twelve most-cited sources. Assistants that search the web quote pages that say plainly what a firm does, for whom, in which languages and at what price.
Directories count. guichet.public.lu, Editus and the OEC directory are among the most-cited websites. Keeping a listing there complete and current costs little.
One assistant is not enough. 27 of the 161 firms were named by a single model version, and 26 by all six. A firm can be named often by one assistant and not at all by the next.
What do AI assistants say about your firm?
Any accounting firm in Luxembourg can ask for its figures from this edition, free. If you also want to know what to change, our free report shows what ChatGPT, Gemini and Google AI Overviews say about your firm in English, French and German, and the first five fixes.
Independence and corrections
Who made this, and how to correct it
- Who we are
- Letzscale sells AI-visibility services, including to accounting firms. That is why the method is published in full. When this edition was collected, no firm in the table was a paying Letzscale client.
- No paid places
- The figures come only from the collected answers. Buying a service from Letzscale does not change a firm's figures, and a firm cannot pay to appear or to be removed from the count.
- Corrections
- If a figure, a name or a firm type looks wrong, write to hello@letzscale.com. We check every request against the collected answers and correct confirmed errors on this page, with the date of the change.
- Not advice
- This page is research into what AI assistants answer. It is not a recommendation of any firm and not professional advice.
- Names
- ChatGPT, Gemini, Claude and Perplexity are products of OpenAI, Google, Anthropic and Perplexity AI. Product and firm names are used only to identify them. Letzscale is not affiliated with, sponsored by or endorsed by these companies or by any firm named on this page.
From Letzscale, the team behind this index
What do AI assistants say about your firm?
Get a free report on what ChatGPT, Gemini and Google AI Overviews say about your firm in English, French and German, plus the first 5 fixes.
We make 7 reports a week, because a person on our team checks every one. Requests after the 7th move to next week.
Only want your firm's figures from this edition?