The Swiss VAT Audit (MwSt-Kontrolle): What the ESTV Checks and How to Prepare

Swiss VAT is a self-assessment tax: you declare and pay it yourself, and the ESTV normally trusts your figures.[2] The counterweight is the MwSt-Kontrolle, the VAT audit any registered business can face. Here is what happens.

Why the ESTV audits, and how far back it goes

The VAT Act (MWSTG) authorises the ESTV to audit taxable persons to clarify the circumstances, with access to your accounts and receipts.[1] Audits keep treatment even-handed in a tax funding about a third of the federal budget.[2]

An audit normally covers every completed, not yet prescribed tax period — usually the last four calendar years.[2] The right to establish the tax prescribes five years after the period ends, in any case ten.[1]

Announcing an audit interrupts that five-year clock, which then runs again for two years — an audit extends how far back the ESTV can reach.[1]

A taxable person may also request an audit, to be performed within two years.[1] Books, receipts and business documents are kept until the claim has prescribed: ten years, twenty for immovable goods.[1]

The phone call, the venue and the set-up

Written notice is the statutory rule; only in justifiable exceptional cases may the ESTV arrive unannounced.[1] In practice the VAT expert calls first to agree date, location, audit period and rough duration, confirmed in writing.[4]

The default venue is your premises in business hours; on request it can move to your fiduciary's office if all records are there.[4] In a one-person business you need not be present throughout.[2]

The expert may also question third parties: clients and suppliers must answer the ESTV free of charge, and records can be demanded.[2] Auditors are themselves bound by confidentiality.[2]

All audit costs are yours: your own time and fiduciary invoices are not reimbursed, so keep your Treuhänder reachable during the audit.[4]

What the auditor actually checks

The audit builds on your books: the expert first checks whether the bookkeeping is formally and materially correct and complete.[3] What pays off is an audit trail (Prüfspur) — every transaction traceable from voucher to return and back.[2]

Turnover first: the expert reviews your invoices, receipts and cash vouchers, assigns rates or exemptions, and compares them with your declared figures.[3] A yearly turnover reconciliation avoids such differences; errors must be corrected by the return covering the 180th day after the business year ends.[3]

Input tax next, checked on supplier invoices, receipts and your input tax journals.[3] Correction keys — say for supplies used both for taxable and exempt purposes — are tested for appropriateness, even under the flat-rate (Saldo-/Pauschalsteuersatz) method.[3]

Nobody reads every receipt: the detailed check targets a representative period — usually a year, sometimes a month — and differences found there are extrapolated across the whole audit period.[3]

From the document list to the assessment notice

The call comes with a document list: balance sheets and profit-and-loss statements, ledgers with VAT codes, the "MWST-Ordner" behind your returns, turnover and input-tax reconciliations, the tax return and assessments, leasing contracts, the AHV payroll declaration, and customer and supplier invoices.[5]

At the end, the findings are discussed and handed over in writing with the corrections attached.[3] The assessment notice (Einschätzungsmitteilung) concludes the audit within 360 days of notification and states the tax claim for the audited periods.[1]

If the result is an additional charge, pay undisputed corrections at once — the earlier, the smaller the default interest.[3] The interest runs from a mid-term due date to your payment; it is not a fine and needs no reminder.[2][1]

The audited periods become binding through your written recognition of the assessment notice, or payment without reservation (Art. 43(1)(b) MWSTG).[1] Until then, both sides can reopen them for two years; if you dispute the findings, demand a formal ruling (Art. 82 MWSTG).[3] Reconcile turnover yearly, keep every voucher — facturio keeps invoices and receipts consistent, so the trail already exists. Sources: [1] Fedlex, VAT Act (SR 641.20); [2] ESTV, VAT audit overview; [3] ESTV, VAT audit procedure; [4] ESTV, scheduling; [5] ESTV, documents.