Corporate tax return in Switzerland

The tax return is an unavoidable annual obligation for every company registered in the Swiss commercial register. Whether it is an LLC, a corporation or a sole proprietorship subject to tax, filing a complete and accurate return on time is essential to avoid penalties and optimise the tax burden.

This guide walks you through the complete corporate tax return process in Switzerland: deadlines, documents, steps, common errors and the advantages of professional support from AX-Fiduciaire.

Filing deadlines by canton

Each canton sets its own deadlines for filing the tax return. Here are the main deadlines for French-speaking cantons and some reference cantons:

Deadlines apply to the previous tax year (e.g. 2025 return filed in 2026). Extensions are generally granted upon a simple motivated request.

At AX-Fiduciaire, we systematically manage extension requests for our clients to allow sufficient time to prepare an optimal return. We nevertheless ensure filing well before the final deadline to avoid any risk.

Documents required for the tax return

Preparing the tax return requires a complete accounting file. Here is the detailed list of required documents:

Mandatory accounting documents

• Balance sheet and income statement: annual financial statements signed by the competent body
• Notes to the annual accounts: additional information required by the CO (art. 959c)
• Depreciation schedule: detail of each asset, acquisition value, accumulated depreciation and depreciation for the year
• Detail of provisions: nature, amount and justification of each provision
• General ledger and journal: detail of all accounting entries for the year

Additional documents

• Schedule of participations: list of participations held with percentage, nominal value and book value
• Detail of loans: loans granted and received, conditions (rate, duration), particularly loans between related companies
• Director remuneration: detail of salaries, bonuses, dividends and benefits in kind paid to directors and managers
• General meeting minutes: minutes approving the annual accounts and the appropriation of profit
• Auditor's report: if the company is subject to limited review or ordinary audit
• VAT returns: the 4 quarterly returns for the year and the annual reconciliation
• Paid-up capital certificate: in case of capital changes during the year

For real estate companies

• Detailed rental schedule (by property and by tenant)
• Detail of maintenance expenses and works carried out
• Estimated fiscal value of properties

The tax return process step by step

Here is how the corporate tax return process works at AX-Fiduciaire:

Step 1: Annual closing

The tax return is based on a rigorous annual closing. We close your accounts by verifying each item of the balance sheet and income statement, posting inventory entries (depreciation, provisions, accruals) and preparing the final financial statements.

Step 2: Tax adjustments

The accounting result is then adjusted to determine taxable net profit. The main corrections are:

• Non-deductible expenses: fines, excessive donations, expenses of a private nature, excess depreciation
• Exempt income: dividends benefiting from the participation deduction, capital gains on qualified participations
• Loss carry-forward: deduction of losses from the previous 7 years still available for carry-forward
• Disallowed provisions: dissolution of provisions without sufficient commercial justification

Step 3: Tax provision calculation

We calculate the tax provision for the year, which itself constitutes a deductible expense. This circular calculation requires a precise estimate of the total tax burden (federal, cantonal, municipal) and capital tax.

Step 4: Completing the return

We complete all the tax forms required by the canton:

• Main legal entity tax return form
• Specific annexes (participations, loans, properties, etc.)
• Federal form (for direct federal tax)
• Supplementary forms depending on the situation (withholding tax, anticipatory tax, etc.)

Step 5: Review and filing

Before filing, we perform a cross-check for consistency between the financial statements, the tax forms and the VAT returns. The return is then filed electronically (where the canton permits) or by mail within the deadlines.

Step 6: Assessment follow-up

After filing, we monitor the assessment process: verification of instalments paid, response to any questions from the administration, review of the final assessment decision and, if necessary, filing a complaint in case of disagreement.

Common errors in tax returns

Our experience reveals that the same errors frequently recur in corporate tax returns. Here are the most common and how to avoid them:

1. Excess depreciation

Exceeding the maximum depreciation rates permitted for tax purposes is a frequent error. The excess will be added back by the tax authority, increasing taxable profit and potentially generating default interest. Our accountants systematically apply the rates published by the FTA.

2. Unjustified provisions

Building provisions without sufficient commercial justification ("smoothing" or "precautionary" provisions without an identifiable risk) will be challenged during an audit. Each provision must correspond to a real, documentable and quantifiable risk.

3. Director's private expenses

Expenses of a private nature of the director-shareholder (luxury vehicle with mixed use, excessive entertainment expenses, works at the private residence) are a frequent audit target. They constitute a hidden profit distribution, taxable as a deemed benefit in money.

4. Non-compliant shareholder loans

Loans from the company to its shareholder must meet market conditions (interest rate compliant with FTA guidelines, borrower's ability to repay). A zero-interest loan or one without any intention of repayment will be reclassified as a profit distribution.

5. Forgetting loss carry-forward

Not carrying forward losses from previous years is a costly but surprisingly frequent error, especially among companies that change fiduciary. Losses can be carried forward for 7 years and must be actively deducted in the return.

6. VAT / tax return inconsistency

The turnover declared for VAT must be consistent with that of the tax return. Unjustified discrepancies trigger in-depth audits. We systematically perform a reconciliation between the two returns.

Tax instalments and payment

In Switzerland, companies generally pay provisional instalments throughout the year, before the final assessment:

It is important to adjust instalments up or down during the year if the current year's profit deviates significantly from the previous year. An instalment that is too low will generate default interest, while one that is too high unnecessarily ties up cash.

Why entrust your return to AX-Fiduciaire?

The tax return is not a simple administrative form. It is a strategic document that determines the amount of tax you will pay for the past year. Here is why our clients entrust us with this task:

• Included in packages: the tax return is included in all our accounting packages, at no extra cost. This is an exception in the fiduciary sector where this service is generally charged CHF 500 to CHF 1,500 extra
• Cantonal expertise: we know the forms, practices and expectations of each French-speaking cantonal tax administration
• Accounting-tax consistency: by managing your accounting and your tax return, we guarantee perfect consistency between the two
• Proactive optimisation: we identify all applicable deductions and tax optimisation strategies before filing
• Post-filing follow-up: we manage the relationship with the tax authority after filing (questions, adjustments, complaints)
• Meeting deadlines: we ensure timely filing and manage extension requests

Typical annual tax calendar for a company

Here is a typical calendar for a company whose financial year corresponds to the calendar year (January-December):

At AX-Fiduciaire, we manage this calendar from start to finish for our clients, ensuring that every deadline is met and every optimisation opportunity is seized.

Good to know: Our accounting packages include bookkeeping, VAT returns, annual closing AND the tax return. All-inclusive, from CHF 149/month. Request a personalised quote.