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Voluntary tax disclosure in Switzerland 2026: back taxes, conditions and heirs

A forgotten account, inherited securities: how the penalty-free voluntary disclosure works, how far back the back tax reaches, and what applies to heirs.

Published on 01.10.2026 · 7 min read

If an account, some securities or a stream of income never made it into your past Swiss tax returns, you can put that right without a fine, but only once in your lifetime. The penalty-free voluntary disclosure (straflose Selbstanzeige) has applied since 01.01.2010 to the direct federal tax and to cantonal and municipal income and wealth taxes. What you still pay is the back tax, called Nachsteuer, plus interest, for at most the last ten years.

Heirs who find something the deceased never declared get a shorter route: only the last three tax periods before the year of death are taxed again.

For foreign accounts covered by the automatic exchange of information, the Federal Tax Administration considers a penalty-free disclosure no longer possible in many cases.

Paying the fare before the inspector arrives

A train ticket bought after boarding, before anyone checks, works the same way. You pay the fare you owed, plus interest, and no surcharge. Wait for the inspector and the surcharge comes on top. And the conductor only lets it go once.

The report has to say what it is: simply writing the account into next year's return doesn't count. Zurich's tax guide puts it bluntly, «die blosse Deklaration ohne Hinweis genügt nicht» (a declaration without a note saying so isn't enough). Aargau calls this a silent declaration and says it leads to criminal proceedings being opened.

Zurich requires the disclosure in writing. Aargau doesn't prescribe a form but recommends writing too. In both cantons it goes to the municipal tax office or to the cantonal tax office.

What has to be true for it to work

It must be your first disclosure, and federal and cantonal law set three conditions:

  1. No tax authority already knows about the evasion.
  2. You support the tax authority without reservation in setting the back tax.
  3. You make a serious effort to pay the back tax.

The report has to come of your own accord, not after the tax office has started asking on a suspicion.

Zurich and Aargau describe what that looks like in practice: a statement listing, for every year affected, the undeclared assets at 31.12 and the undeclared income, along with any debts and new deductions. Zurich wants everything converted to francs using the Federal Tax Administration's Kursliste: the year-end rate for assets, the annual average for income. Where records are missing, values are estimated realistically and marked as estimates. Balance and interest statements, securities tax statements and pension certificates go with it.

The disclosure covers income and wealth tax. Everything else stays owed in full, VAT and AHV contributions included, and withholding tax needs a separate disclosure, according to the Federal Tax Administration.

How far back does the back tax go?

The back tax is the tax that should have been paid at the time, plus interest. The law lets the tax authority open back-tax proceedings up to ten years after the end of the tax period, and the amount has to be fixed within 15 years.

So if an account sat forgotten for twenty years, a disclosure means paying for the last ten, not all twenty.

The fine for tax evasion is normally equal to the evaded tax and moves with fault. A penalty-free disclosure saves it.

A CHF 300 gap a year, before interest

Take a savings account that hasn't been declared for at least ten years. Assume the tax on it (wealth tax plus income tax on the interest) would have come to CHF 300 a year; the figure is made up. The table shows the unpaid tax before interest; this article does not work out the interest.

RouteTax, before interestFine
First disclosureCHF 3'000 (ten years)none
Any later disclosureCHF 3'000one fifth of the evaded tax: CHF 600
Found by the tax officeCHF 3'000a third to three times the evaded tax: CHF 1'000 to CHF 9'000
Heirs, simplified procedureCHF 900 (three periods)none

The fines in the second and third rows assume the evaded tax equals the CHF 3'000. The tax office has to prove that amount, and it can come out lower than the back tax. Where a discovered case lands in the range depends on fault, and the Federal Tax Administration gives evasion over several tax periods as an example of serious fault.

In this sum, disclosing instead of being found changes only the fine.

When the money came from someone who died

Heirs usually didn't do the evading themselves, so the law goes easier on them. The back tax covers those three periods, with late-payment interest. Heirs aren't fined for the deceased's evaded tax.

The conditions mirror the disclosure: no tax authority knows yet, the heirs cooperate without reservation, and they make a serious effort to pay. Each heir has this right independently of the others, and in Zurich and Aargau a report by a single heir is enough. An executor or estate administrator can request it too.

In Zurich and Aargau, the report goes into the inventory questionnaire the heirs receive from the municipal tax office after the death. The route is closed if the estate is liquidated by the authorities or in bankruptcy. If heirs don't report, or report only later, Aargau says the simplified procedure is no longer available, and ordinary back-tax proceedings follow for up to ten tax periods. Knowingly hiding estate assets can bring separate criminal proceedings.

Why the automatic exchange changes the maths

Through the automatic exchange on financial accounts, Switzerland receives data on accounts and securities held abroad. Aargau lists what therefore counts as known to the tax authorities: account number, name, address, date of birth and balance. That hits the first condition: what the authority already knows can't be reported of your own accord.

The Federal Tax Administration assumes that knowledge for items covered by the exchange from 30.09.2018 at the latest. For items that only exist after 2017, and for states that join the exchange later, the date is 30 September of the year in which the first exchange on them takes place. The cantonal tax administration decides each case. For a forgotten account in a partner state, the penalty-free route is often closed; back tax and any fine then follow the ordinary rules.

Crypto-assets have their own exchange in the pipeline, covered in Crypto and the automatic exchange of information in 2026. The Federal Department of Finance's page covers only the exchange on financial accounts and says nothing about crypto-assets.

What goes into the return afterwards

TaxWize doesn't prepare a voluntary disclosure. That runs between you and the tax office, with professional tax advice alongside if you want it.

After that, the account belongs in every new return. There, TaxWize reads the bank and securities statements you upload, and every value the AI reads can be checked and corrected. For how the tax value at 31 December comes about, see Your Swiss securities register. The tax comparison estimates what your income costs in tax in your municipality.

Sources

Frequently asked questions

What does a penalty-free voluntary disclosure cost?
The fine goes, the tax doesn't. You still owe the back tax (Nachsteuer), meaning the tax that wasn't paid, plus interest, for at most the last ten years. Other levies such as withholding tax, VAT or AHV contributions stay owed as well, and the Federal Tax Administration requires a separate disclosure for withholding tax.
Can I just add the account to my next tax return?
No. Zurich and Aargau both state that listing previously undeclared assets without comment is not a voluntary disclosure. The report has to be recognisable as one. Aargau writes that this kind of silent declaration leads to criminal proceedings being opened.
Can I disclose penalty-free a second time?
No. Penalty-free disclosure is available once in a lifetime, and the cantons report every completed disclosure to the Federal Tax Administration to make sure of it. Any further disclosure that meets the same conditions has its fine reduced to one fifth of the evaded tax, instead of the usual fine of the full evaded amount.
I inherited and found an undeclared account. What applies?
Heirs have a simplified back-tax procedure. Only the last three tax periods before the year of death are taxed, with late-payment interest, and heirs are not fined for the deceased's evaded tax. No tax authority may already know about the evasion. Whether the conditions are met in your case is for the cantonal tax office to assess.
Is a penalty-free disclosure still possible for a foreign account?
Often not, in the Federal Tax Administration's view. For items covered by the automatic exchange of information, it assumes the authorities have known since 30.09.2018 at the latest, and for states that joined later from 30 September of the year of the first exchange. The cantonal tax administration decides whether that applies to your account.

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