Every entry below is the rule as Switzerland publishes it. It is a reference, not a calendar: where a deadline runs from something only you know, this page says so instead of showing a date.
This is the rule as published by the registry, checked against the primary source on the date shown. It is not your filing date. Where a deadline runs from incorporation, from a fiscal year the company itself elects, or from an event only you know about, no date can be derived here at all — the figure you see is the formula, not the answer. Extensions, transitional regimes and entity-specific exemptions are not reflected. Confirm with the registry before you rely on a date.
The Swiss financial year is not fixed by statute. The Confederation's SME portal states that «The financial year generally covers a 12-month period and corresponds to the calendar year (January 1–December 31)» and that «An entrepreneur may, if necessary, choose a different date», adding for the closing date that «The dates for closing accounts normally correspond to the end of the calendar year. A company may, however, choose a different date to suit its requirements.» The financial year end is therefore a date the user must supply, and no deadline counted from it is shown here as a calendar number. Three separate clocks run in Switzerland and must not be confused. The ordinary general meeting that approves the annual accounts runs from the end of the financial year: «Die ordentliche Generalversammlung findet jährlich innerhalb von sechs Monaten nach Abschluss des Geschäftsjahres statt» (Art. 699 para. 2 CO). The VAT return runs from the end of the VAT reporting period — a calendar quarter, half-year or year — and not from the financial year at all. The profit tax return runs on a cantonal calendar date tied to the calendar year in which the financial year closed, which is why it is recorded here on a fixed basis and not as an offset from the financial year end.