Administrative assistance in tax matters

From the fiscal exception to the OECD standard

Until 2009 Switzerland granted administrative assistance in tax matters only to a small number of treaty partners and, in most cases, only in cases of tax fraud. The decisive turn came on 13 March 2009. Under the threat of being placed on an OECD list of uncooperative jurisdictions, the Federal Council announced that Switzerland would adopt the standard of Article 26 of the OECD Model Convention and withdraw its reservation to that article.¹ The new standard requires the exchange of information that is “foreseeably relevant” to the administration or enforcement of the domestic tax laws of the requesting state. It no longer distinguishes between tax fraud and tax evasion. Nor may the requested state refuse assistance on the ground that the information is held by a bank. Part G of this book describes how the negotiation of the revised treaties unfolded and how the UBS affair accelerated it. This section describes the legal regime that resulted.

The domestic procedure is governed by the Federal Act of 28 September 2012 on International Administrative Assistance in Tax Matters, known in German as the Steueramtshilfegesetz (StAhiG) and in English as the Tax Administrative Assistance Act (TAAA). The Act regulates the execution of administrative assistance in the exchange of information on request and in the spontaneous exchange of information under double taxation agreements and other international agreements.² The Federal Tax Administration in Bern is the competent authority. Its implementing ordinance and, subsidiarily, the Federal Administrative Procedure Act complete the framework. The international bases are the double taxation agreements, the tax information exchange agreements concluded with states that have no double taxation agreement with Switzerland, and the multilateral Convention on Mutual Administrative Assistance in Tax Matters of the Council of Europe and the OECD.³

Two features distinguish the tax channel from criminal mutual assistance. First, it is conducted between administrative authorities, the Federal Tax Administration on the Swiss side and a foreign tax authority on the other. Second, the information obtained may in principle be used for tax assessment, while its use in criminal proceedings depends on the terms of the applicable treaty. The requirement of dual criminality does not apply. Instead, the Federal Tax Administration examines whether the information requested is foreseeably relevant and whether the request meets the formal requirements of the treaty.

Foreseeable relevance and fishing expeditions

The Act sets out three grounds on which a request will not be considered. A request is inadmissible if it constitutes a fishing expedition, if it asks for information not covered by the administrative assistance provisions of the applicable agreement, or if it violates the principle of good faith, “particularly if it is based on information obtained through a criminal offence under Swiss law”.⁴ The notion of the fishing expedition marks the outer limit of foreseeable relevance. A request that seeks to find out whether a taxpayer has any assets in Switzerland at all, without a concrete basis, is a fishing expedition. A request that describes a taxpayer, gives reasons to believe that he holds an account at a Swiss bank and explains the tax purpose is not.

The Federal Supreme Court has construed the requirement of foreseeable relevance generously in favour of the requesting state. The Swiss authorities are not to examine the merits of the foreign tax assessment. They must satisfy themselves only that the information requested may be relevant to it. The Court also applies a presumption of good faith to the statements of the requesting state. Swiss authorities must rely on the facts presented in the request unless these are manifestly wrong or contradictory, or unless concrete evidence shows that the requesting state has acted in bad faith.

Group requests and list requests

The most important development in the practice of the last decade was the acceptance of requests that do not name the taxpayers concerned. A group request describes a category of persons by a pattern of behaviour, for example all clients of a particular bank who were resident in the requesting state, held an account during a certain period and did not respond to the bank’s request to confirm their tax compliance. The revised commentary to Article 26 of the OECD Model Convention of 2012 recognised that such requests may be admissible. Switzerland amended its Act accordingly.⁵

The Federal Supreme Court confirmed the admissibility of group requests in a leading judgment of September 2016 concerning a request from the Netherlands. The Dutch tax authority had asked for information on unnamed clients of a Swiss bank who, despite written requests, had not proved that their accounts were declared. The Court held that such a request satisfied the standard of foreseeable relevance and did not amount to a prohibited fishing expedition. It reversed the Federal Administrative Court, which had refused assistance, and confirmed the final decision of the Federal Tax Administration.⁶

The Act contains special rules on the notification of the persons concerned by a group request. At the request of the Federal Tax Administration, the bank or other information holder must identify the persons covered. The Administration notifies those resident in Switzerland directly. It asks the information holder to notify persons resident abroad and to invite them to designate a person in Switzerland authorised to accept service. In addition, the Administration notifies all persons concerned anonymously by publication in the Federal Gazette, and a person who does not respond within twenty days of that publication loses the chance to participate before the final decree.⁷ The anonymised notices in the Federal Gazette, with their long series of initials, dates of birth and nationalities, became a familiar sight for readers of the official publication in the years after 2014.

A different category is formed by list requests, which identify taxpayers not by name but by account numbers or other data. The most important case arose from a French request of 2016 concerning around 40,000 accounts at UBS, based on lists that German authorities had seized in the course of their own investigations and passed on to France. The numbers were substantial. In January 2017 Swiss public broadcasting reported that the Federal Tax Administration had received 66,553 requests in 2016 alone, largely because of such bulk requests, compared with 2,791 in the previous record year of 2014. France headed the list of requesting states.⁸

The Federal Administrative Court refused assistance. The Federal Supreme Court reversed that decision in a judgment of 26 July 2019, published as BGE 146 II 150. It characterised the French request as a list request, in which the persons concerned were identifiable through their account numbers. The Court found that the request was not a fishing expedition. The lists had been discovered in criminal investigations, and a sample verification had shown that a very large proportion of the identified account holders were French taxpayers. On the principle of good faith, the Court relied on the assurances France had given in July 2017. France had undertaken to use the information only in a tax context and not in the criminal proceedings it was conducting against UBS itself.⁹ The judgment was politically sensitive because the bank was at the same time a defendant in French criminal proceedings for unlawful solicitation and aggravated laundering of tax fraud proceeds, which Part G describes. The Swiss court thus had to ensure that the administrative assistance channel would not be used to supply evidence against the Swiss bank itself.

Stolen data and the principle of good faith

The question of stolen data has occupied Swiss courts since former bank employees began selling client data to foreign tax authorities in the late 2000s. Germany bought several data carriers from Swiss banks, and France obtained the data that Hervé Falciani had taken from the Geneva subsidiary of HSBC. Switzerland responded by including in the Act the rule that a request is inadmissible if it violates good faith, in particular if it is based on information obtained through a criminal offence under Swiss law. The case law has given this rule a narrower meaning than its wording might suggest.

The starting point is a French request concerning two taxpayers whose names came from the Falciani data. France had committed itself in 2010 not to use the Falciani data for requests for administrative assistance. In a judgment of 17 March 2017, the Federal Supreme Court held that this unilateral undertaking created legitimate expectations that were protected under the principle of good faith. Because there was a causal link between the stolen data and the request, the Court upheld the refusal of assistance.¹⁰ A month earlier, in a different French case, the Court had interpreted the reference to “punishable acts under Swiss law” in the Swiss-French treaty as meaning acts actually punishable in Switzerland, and had held that the treaty did not permit a refusal based solely on how the requesting state had obtained the underlying data.¹¹

The cases concerning India completed the picture. India had received part of the Falciani data from France through spontaneous exchange and based a series of requests on it. The Federal Tax Administration first refused them. After India reconfirmed its request, the Administration granted assistance in 2019, and the Federal Supreme Court approved that decision in a judgment of March 2021. The Court distinguished two situations. A state that buys Swiss bank data in order to use it for requests acts in bad faith. A state that merely uses data it received through spontaneous assistance from another state does not. Since there was no evidence that India had paid for the data, the request was admissible.¹²

The result is a pragmatic compromise. Switzerland protects itself against states that actively trade in stolen data, while accepting that such data, once circulated among tax administrations, can no longer be kept out of the system. For clients of Zurich banks whose names appeared on leaked lists, the practical consequence is that the origin of the data offers little protection unless the requesting state itself bought it or promised not to use it.

Subsidiarity, professional secrecy and recent case law

Treaties based on the OECD standard require the requesting state to have exhausted the usual sources of information available under its domestic procedure before asking Switzerland. The Federal Supreme Court has consistently treated a declaration to that effect by the requesting state as sufficient. In a French case of April 2018 it held that such a declaration satisfies the principle of subsidiarity at the time of the request. Information obtained by the taxpayer during pending proceedings did not retroactively render the request inadmissible, and the burden of showing that foreseeable relevance had disappeared lay with the party asserting it.¹³ A more recent judgment concerned a request from the Israeli tax authority relating to 794 accounts held by Israeli residents. The Court accepted the appeal as raising a legal question of principle under Article 84a of the Federal Supreme Court Act. It held that the principle of subsidiarity does not oblige the requesting state to contact the taxpayer first if its own law does not require it, and that Switzerland retains discretion to grant assistance even where subsidiarity has not been fully respected.¹⁴

Professional secrecy has also been tested. In a judgment of 4 May 2026, the Federal Supreme Court held that documents which a lawyer had submitted to a cantonal tax administration on behalf of a client could be transmitted to a foreign tax authority. Attorney-client privilege protects communications held by the lawyer or exchanged between lawyer and client. It does not extend to information that a tax authority has received from a lawyer or to correspondence with the lawyer that is in the authority’s possession.¹⁵ For advisers who prepare voluntary disclosures or ruling requests in Zurich, the decision is a reminder that documents lodged with the tax authorities can travel further than intended.

Notification, appeals and subsequent notification

The persons concerned by a request have procedural rights, which are narrower than in criminal mutual assistance but still significant. The Federal Tax Administration informs them of the request and of the main content. It notifies persons resident in Switzerland directly. For persons resident abroad, it asks the information holder to inform them or, failing that, publishes a notice in the Federal Gazette.¹⁶ The final decree may be appealed to the Federal Administrative Court in St. Gallen. Orders preceding the final decree, including orders concerning compulsory measures, may be enforced immediately and challenged only together with it. The appeal has suspensive effect, and in principle only one exchange of written submissions takes place.¹⁷ A further appeal to the Federal Supreme Court is admissible only if the case raises a legal question of fundamental importance or is otherwise particularly important.

The Act also allows notification after transmission. Exceptionally, the Federal Tax Administration notifies the persons concerned only after the information has been transmitted, where the requesting authority shows that prior notification would compromise the purpose of the assistance and the success of its investigation.¹⁸ Once the information has left Switzerland, the person concerned can in substance only seek a finding that the transmission was unlawful. Subsequent notification remains the exception, and the requesting state must give reasons for it in each case.

Peer review and spontaneous exchange

The Global Forum on Transparency and Exchange of Information for Tax Purposes evaluates its members in peer reviews. In the second round, published in April 2020, Switzerland was rated “largely compliant” with the standard of exchange of information on request. The Federal Council noted “significant improvements, in particular as regards bearer shares and the efficiency of information exchange in practice”, while the Forum made recommendations on several specific points.¹⁹ The rating places Switzerland in the same category as most major financial centres.

Spontaneous exchange of information in tax matters developed in parallel. Its main application in Switzerland concerns tax rulings. Under the multilateral convention and the Act, the Federal Tax Administration transmits information on advance tax rulings to the states concerned. Rulings issued since 2017 must be transmitted within three months, and the cantonal tax administrations must report their rulings to the Federal Tax Administration within sixty days. The taxpayer is notified before transmission and has ten days to comment.²⁰ For multinational groups with principal companies or financing entities in Zurich, the spontaneous exchange of rulings means that tax arrangements agreed with the cantonal tax office become known to the tax authorities of the states in which the group operates.

Notes

1. Federal Council, media release “Die Schweiz will den OECD-Standard bei der Amtshilfe in Steuersachen gemäss Art. 26 des OECD-Musterabkommens übernehmen”, 13 March 2009, https://www.admin.ch/gov/de/start/dokumentation/medienmitteilungen.msg-id-25863.html (withdrawal of the reservation to Art. 26). The background is described in Part G. The press release of 2 April 2009 in which the President of the Confederation took note of the OECD list is at https://www.admin.ch/gov/de/start/dokumentation/medienmitteilungen.msg-id-26261.html. ↩
2. Art. 1 TAAA, Federal Act of 28 September 2012 on International Administrative Assistance in Tax Matters, SR 651.1, English text at droit-bilingue.ch, https://www.droit-bilingue.ch/de-en/6/65/651.1-1-4.html. ↩
3. Federal Tax Administration (ESTV), “Amtshilfe auf Ersuchen (EOIR)”, https://www.estv.admin.ch/de/amtshilfe-auf-ersuchen-eoir, section on legal bases. ↩
4. Art. 7 TAAA, English text at droit-bilingue.ch, https://www.droit-bilingue.ch/de-en/6/65/651.1-7-12.html. ↩
5. Federal Council, Botschaft zur Änderung des Steueramtshilfegesetzes of 16 October 2013, BBl 2013 8369, https://www.fedlex.admin.ch/filestore/fedlex.data.admin.ch/eli/fga/2013/1632/de/pdf-a/fedlex-data-admin-ch-eli-fga-2013-1632-de-pdf-a.pdf, which quotes the passage on group requests in the revised commentary to Article 26 of the OECD Model Convention published on 18 July 2012. The definition of group requests in Art. 3 lit. c TAAA was inserted by the Federal Act of 21 March 2014 and entered into force on 1 August 2014 (AS 2014 2309), https://www.droit-bilingue.ch/de-fr/6/65/651.1-3-6.html. ↩
6. Federal Supreme Court, BGE 143 II 136, judgment 2C_276/2016 of 12 September 2016 (Netherlands; admissibility of group requests without names under Art. 26 DTA CH-NL and the mutual agreement on paragraph XVI of the Protocol), https://www.servat.unibe.ch/dfr/bge/c2143136.html. ↩
7. Art. 14a TAAA, English text at droit-bilingue.ch, https://www.droit-bilingue.ch/de-en/6/65/651.1-14a-20.html. ↩
8. SRF News, “Kampf gegen Steuerbetrug – Ausländische Amtshilfe-Begehren steigen auf Rekordwert”, 25 January 2017, https://www.srf.ch/news/schweiz/kampf-gegen-steuerbetrug-auslaendische-amtshilfe-begehren-steigen-auf-rekordwert. The article mentions a French request concerning approximately 45,000 UBS accounts. ↩
9. Federal Supreme Court, BGE 146 II 150, judgment 2C_653/2018 of 26 July 2019 (France; Art. 28 DTA CH-FR; foreseeable relevance and fishing expedition; speciality principle and secrecy), https://www.servat.unibe.ch/dfr/bge/c2146150.html. ↩
10. Federal Supreme Court, BGE 143 II 224, judgment 2C_1000/2015 of 17 March 2017 (France; Falciani data; binding unilateral undertaking; Art. 7 lit. c TAAA), https://www.servat.unibe.ch/dfr/bge/c2143224.html. ↩
11. Federal Supreme Court, BGE 143 II 202, judgment 2C_893/2015 of 16 February 2017 (France; Art. 28 para. 3 lit. b DTA CH-FR; Art. 7 lit. c TAAA; notion of punishable acts under Swiss law), https://www.servat.unibe.ch/dfr/bge/c2143202.html. ↩
12. Federal Supreme Court, judgment 2C_750/2020 of 25 March 2021 (India; Falciani data received via spontaneous exchange; no purchase), https://search.bger.ch/ext/eurospider/live/it/php/aza/http/index.php?highlight_docid=aza%3A%2F%2F25-03-2021-2C_750-2020&lang=it&zoom=&type=show_document, with references to judgments 2C_648/2017 of 17 July 2018 and 2C_619/2018 of 21 December 2018. ↩
13. Federal Supreme Court, BGE 144 II 206, judgment 2C_28/2017 of 16 April 2018 (France; subsidiarity; foreseeable relevance; good faith), https://www.servat.unibe.ch/dfr/bge/c2144206.html. ↩
14. Adrien Pasquarello, “Administrative assistance in tax matters: Subsidiarity, a principle without substance?”, Centre de droit bancaire et financier (CDBF), Université de Genève, 23 October 2025, https://cdbf.ch/en/1438/, discussing Federal Supreme Court judgment 2C_352/2024. ↩
15. Joël Pahud, “Administrative Assistance in Tax Matters: Correspondence between a lawyer or notary and third parties”, CDBF, 18 June 2026, https://cdbf.ch/en/1467/, discussing Federal Supreme Court judgments 2C_506/2024 of 4 May 2026 and 7B_1144/2025 of 20 May 2026. ↩
16. Federal Tax Administration, “Amtshilfe auf Ersuchen (EOIR)”, https://www.estv.admin.ch/de/amtshilfe-auf-ersuchen-eoir, section on notification. ↩
17. Art. 19 TAAA, English text at droit-bilingue.ch, https://www.droit-bilingue.ch/de-en/6/65/651.1-19-26.html. ↩
18. Art. 21a TAAA, English text at droit-bilingue.ch, https://www.droit-bilingue.ch/de-en/6/65/651.1-21a-29.html. ↩
19. Swiss Federal Council, “Global Forum: Switzerland scores well”, media release of 6 April 2020, https://www.admin.ch/gov/en/start/documentation/media-releases.msg-id-78708.html. ↩
20. Federal Tax Administration, “Spontaneous Exchange of Information SEOI”, https://www.estv.admin.ch/en/spontaneous-exchange-of-information-seoi. Exchange takes place only with states party to the multilateral Convention on Mutual Administrative Assistance in Tax Matters. ↩

For general information only. This article does not constitute legal or tax advice, does not replace advice on an individual case and creates no lawyer-client relationship. It reflects the legal position as of September 2025.