Which tax advisors does AI recommend in Vienna?
We asked ChatGPT, Perplexity, Gemini and Google's AI Mode the same question. More than 30 firms were named, but not a single one by all four. On tax advisors the AIs disagreed even more than on restaurants.
🇩🇪 Diese Studie auf Deutsch lesenMore and more clients no longer ask Google, they ask AI: “Who is a good tax advisor in Vienna?” For a firm that means: whoever gets named wins the client, whoever is missing is invisible to those searchers. So we asked four AIs. The result is surprisingly split.
Across four AI engines, around 30 different firms were recommended, but not a single one made it into all four. Worse: the AIs fell into two camps that barely overlapped.
The experiment
On 11 June 2026, from a Vienna-based browser, we put the exact same question, word for word, to all four major AI engines:
The result: two worlds
Instead of a shared top group, we got two almost separate lists:
- ChatGPT, Gemini and Google AI Mode mostly named large, award-winning firms, above all TPA and Treuhand-Union, plus BDO and Deloitte.
- Perplexity named something entirely different: small firms with 5.0-star ratings on Google, such as Mag. Veronika Weiß, F+H or Kytax.
Only the Gemini result partly overlapped with both lists. Across all four engines, though, no firm made it into every answer:
And this is what each engine's list looked like, along with the sources it drew on:
| Engine | Names, among others | Draws on |
|---|---|---|
| ChatGPT | Treuhand-Union, TPA, BDO, Deloitte (+ Google Maps list) | webempfehlung.at, own websites, Google reviews |
| Perplexity | Veronika Weiß, F+H, Kytax, Kowarik & Waidhofer … (by Google stars) | almost only one source (steuerexperten.at) |
| Gemini | steuerexperten.at, ai.tax, steuerquadrat, Treuhand-Union, TPA | Google knowledge, no visible individual sources |
| Google AI Mode | TPA, Treuhand-Union, Deloitte, BDO, Simplify Tax, ASKG | wirtschafts-nachrichten.at (awards), herold.at, Google profiles |
A firm can sit right at the top in ChatGPT and not exist at all in Perplexity.
Why so different? The sources decide
AI does not invent recommendations, it repeats what its sources say. And here the sources differ:
- ChatGPT, Gemini and Google AI Mode rely on awards and press, such as the title “Tax Advisor of the Year”, which TPA Wien won in 2025 and 20262, plus firm comparisons (webempfehlung.at) and industry listings (herold.at)3. Whoever is honored there gets named.
- Perplexity relied almost entirely on one source, steuerexperten.at1, and sorted by Google stars. That puts small firms with 5.0 stars right at the top.
What this means: a firm that wins awards can be invisible in Perplexity, and one with lots of good Google reviews may not show up in ChatGPT. The two engines judge by completely different criteria.
Careful: AI gets it wrong here too
- 5.0 stars says little. Several of Perplexity's “top” firms had only 1 to 3 reviews, a top score from three people is not a reliable statement.
- “Best” is not objective. There is no shared winner. Which firm the AI names depends solely on which source it happens to favor, awards or Google stars.
- Awards have to be checked too. The “Tax Advisor of the Year” award is given by IFA, “Die Presse” and LexisNexis, not by the news portal that merely reports on it.
What this means for Vienna's firms
For Vienna's tax firms it means, concretely: you have to serve both camps, otherwise you stay invisible in half of the AIs.
- For Perplexity & co.: a well-kept Google Business profile with lots of genuine reviews, and entries in the relevant directories (e.g. herold.at, firmenabc.at).
- For ChatGPT, Gemini & Google: awards, press and expert comparisons, plus a website that describes your focus areas, location and services in a machine-readable way.
- For all of them: a consistent name across every source. That is what the AI builds its answer from.
Visibility in AI can be built deliberately. This approach is called Generative Engine Optimization (GEO), and it is what KIGEO specializes in.
Does AI name your firm?
We check for free whether ChatGPT, Perplexity, Gemini & Google recommend your tax firm, and show you who gets named instead.
free AI visibility check →Methodology & sources
All engines were queried on 11 June 2026 with the exact wording quoted above, from a Vienna-based browser (one answer per engine). Firms named were recorded by name; award claims were checked against the cited sources. Sources used:
- steuerexperten.at, the source from which Perplexity drew nearly all its names for this answer (by Google reviews).
- “Tax Advisor of the Year”, an Austrian award from IFA AG, “Die Presse” and LexisNexis (with the KSW); TPA won Vienna in 2025 and 2026 (a source of Google AI Mode & ChatGPT, among others).
- Herold, Tax advisors Vienna (business directory).
- webempfehlung.at, firm/service-provider comparison (named as a source by ChatGPT).
- Local Falcon, The AI Visibility Crisis, context: in ChatGPT, only about one in six local businesses ever shows up.
- Omni Search Labs, search experiment, context: for “best”-style questions, AI engines return very different lists.