The tax year is the business year. Thus, the basis for corporate taxation is the applicable accounting period, which may end at any date within a calendar year.
The tax system for corporate income and capital taxes is based on taxpayers' declarations, with subsequent assessments being issued by the tax authorities on the basis of the tax returns filed. The tax return has to be filed annually (an exemption exists in the first business year in case an extended business year shall apply). The filing deadlines vary from canton to canton (usually between six and nine months after the close of the business year). Companies are initially assessed on a provisional basis, with the final assessments being issued after the tax base was either subject of a tax audit or declared final by the authorities.
Payment of tax
Unless instalment payments are specifically requested, federal, cantonal, and communal taxes on income and capital are, in most cantons and for federal tax purposes, payable only upon receipt of a demand based on a provisional or final assessment.
Note that cantonal exceptions apply. As an example, based on the date of maturity of the respective tax year (30 September), the canton of Zurich levies late payment interest to the extent that the full (final) tax amount had not been paid in time (independent from any earlier provisional tax invoices). About one month before the due date, a (provisional) tax bill based on the latest tax return filed or the assessment of the preceding period is sent to the taxpayer. Payment is usually made in two or three instalments. If the entire amount is paid up front, a discount may be granted.
The provisional federal CIT is usually due by 31 March of the year following the tax period at question. The due date of the final federal CIT and the provisional or final cantonal CIT varies.
Tax audit process
Swiss CIT law does not outline specifics of the tax audit process. At first, the tax authorities review the tax return and its enclosures as filed by the taxpayer. Such review is usually desk-related work. The competent tax authorities are obligated and entitled to clarify all relevant information necessary to assess taxpayers on a true and complete base. The tax authorities may request further information/documentation or may inspect the taxpayer’s premises.
Statute of limitations
As a general rule, the right to assess a taxpayer in relation to corporate income and capital taxes expires five years after the end of the corresponding tax period (relative statute of limitations). Under certain conditions (e.g. where the relative statute of limitations is interrupted), the absolute statute of limitations of 15 years applies.
In case of tax fraud (‘Steuerbetrug’) or tax evasion (‘Steuerhinterziehung’; e.g. where specific information was not available to the tax inspector at the time of the assessment), finally assessed tax periods can be reopened. The statute of limitations to reopen finally assessed tax periods is ten years after the end of the corresponding tax period.
Topics of focus for tax authorities
The Swiss tax authorities do not communicate specific topics of focus. The tax authorities do normally start their assessment with reviewing the tax return and its enclosures as filed by the taxpayer (see Tax audit process above).