Generally due 12 months after the end of the company's fiscal year. For a company with a 31 December year-end, the return for 2024 is typically due 31 December 2025. In practice, cantons issue filing deadlines in their individual cantonal rules, often defaulting to 30 June following the tax year, with extensions available. Many cantons grant automatic extensions to companies using a licensed fiduciary (Treuhänder).

Federal & Cantonal Corporate Tax Return (Steuererklärung juristische Personen)

The annual corporate income tax return filed with the cantonal tax authority, covering both the direct federal tax (Direkte Bundessteuer / DBSt) and cantonal and communal taxes (Staats- und Gemeindesteuer / StGSt). A single return filed with the canton covers all three levels of Swiss corporate tax.

Who this applies to

  • Swiss AG
  • Swiss GmbH
  • Branches of foreign companies with Swiss fixed establishment
  • Cooperative societies
  • All other legal entities with Swiss tax residence

What to file

Completed cantonal Steuererklärung form covering: income statement (Erfolgsrechnung), balance sheet (Bilanz), calculation of taxable profit, capital tax base calculation, list of participations, transfer pricing disclosures for transactions with related foreign entities, and signed declaration.

How to file

Filed electronically via the cantonal tax portal (e.g. SuissTax in most cantons, GeTax in Geneva, Zurich's online tax portal). Paper filing remains available in most cantons but is increasingly discouraged. A licensed Treuhänder (fiduciary) typically handles filing on behalf of the company.

Payment due

Provisional invoices (Akontozahlungen) are issued by the canton during the year based on prior year liability. Final payment or refund is due 30 days after the final tax assessment notice (Veranlagungsverfügung) is issued — which may be months or years after the return is filed.

Penalties for missing this deadline

Failure to file by the deadline results in a written reminder (Mahnung). Continued non-compliance leads to a penalty assessment (Veranlagung nach Ermessen) where the canton estimates taxable income. Late interest (Verzugszins) applies from the due date at the cantonal rate (typically 0.5–1.5% per year). Deliberate non-filing is a criminal offence (Steuerhinterziehung).

Filing checklist

  • Completed and signed Steuererklärung form for the applicable canton
  • Audited or reviewed annual accounts (Jahresrechnung): income statement + balance sheet + notes
  • Depreciation and provisions schedule
  • List of participations held (name, %, book value)
  • Summary of related-party transactions (if any) for transfer pricing
  • MWST registration number
  • Prior year final assessment for reference

Common mistakes to avoid

  • Missing the extended cantonal deadline (not all cantons grant the same extension)
  • Failing to include details of foreign subsidiary dividends, which affect the participation deduction calculation
  • Omitting Kapitalsteuer base calculation (equity schedule)
  • Not reconciling the statutory accounts to the tax accounts (Steuerbilanz adjustments)
  • Assuming the federal and cantonal rates are the same — they use the same return but different rate schedules

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