Tax arrears: when the delay turns into a bill

In Switzerland, the cost of submitting your tax return after the deadline varies from canton to canton. In some places, requesting an extension is free of charge provided the procedure is followed correctly. In others, simply requesting an extension becomes a source of revenue for the tax authorities, with fees of up to 60 francs, according to information reported by Econostrum.

For an SME, a self-employed person or a tax adviser, the issue goes far beyond mere administrative convenience. Missing a deadline can trigger fees, reminders, interest charges, or even an ex officio assessment. And when several deadlines pile up — cantonal tax, direct federal tax, VAT, wages, social insurance contributions — tax arrears can quickly put a strain on cash flow and on the relationship with the tax authorities.

An extension is not a delay, but it can still incur costs

The first misunderstanding stems from the terminology. Requesting an extension within the deadline is not the same as submitting a late return without taking any action. An extension is a formal request: it aims to postpone the filing deadline when the accounts are not ready, supporting documents are missing, or the accountancy firm is dealing with a peak in workload. A delay, on the other hand, begins when the applicable deadline has passed without a valid request having been made.

This distinction is essential for businesses. A company awaiting the completion of its accounts, the finalisation of a stock take, confirmation of a bank balance or the approval of a provision may need time. But this time must be managed effectively. Under the Swiss tax system, filing deadlines vary by canton and generally fall between 31 March and 30 June, according to the research file. In Geneva, the initial deadline is generally set at 31 March. In the canton of Vaud, the date specified for legal entities is 30 June.

The comparison published by Econostrum shows, above all, that the cost of an extension depends heavily on the taxpayer’s tax domicile or registered office. In Bern, the return must normally be filed by 15 March. An online extension until 15 July remains free of charge, but a longer extension incurs a fee: 20 francs until 15 September, then up to 40 francs to extend until November. Applications made by post, email or in person may cost more, up to 60 francs. The same extension request can therefore be handled differently depending on how the application is submitted.

This is a very practical issue for trust companies. The channel used, the timing of the request and the canton concerned can all affect the final cost to the client. The individual fee may seem modest, but in a portfolio containing numerous mandates, or for a firm managing several related taxpayers, these costs become an organisational issue.

Bern, Geneva, Valais: deferral as a source of administrative revenue

The debate has flared up because these fees are by no means trivial for certain authorities. According to Econostrum, the canton of Bern collected around 3.5 million francs in 2024 thanks to deadline extensions. The same article states that around 70 per cent of taxpayers in Bern do not submit their tax returns by the original deadline. In other words, deadline extensions are no longer isolated cases: they form part of the normal running of the tax season.

Geneva also operates a fee-based system. The initial deadline there is set at 31 March. A three-month extension costs 20 francs, a five-month extension 40 francs, and an extension of more than five months 60 francs, according to figures cited by Econostrum. Nearly 68,000 taxpayers in Geneva apply for an extension each year. For an urban canton where many self-employed people, business owners and employees with complex circumstances need to gather supporting documents, this is no mere theoretical issue.

Valais follows a similar approach: an extension until the end of July, then until the end of October and, in certain exceptional cases, until the end of December. Each extension costs 20 francs, except for requests made by tax advisers via a dedicated portal, which are charged at five francs, according to Econostrum. In 2024, these extensions brought in around 860,000 francs for the canton.

For an SME, the lesson is simple: the tax mandate does not begin when the tax return is filed, but as soon as the accounts are finalised. The later the accounts are finalised, the less room for manoeuvre there is. Small businesses are particularly vulnerable, as the same person often juggles management, sales, administration, supplier payments and sending documents to the accountancy firm. A late tax return is therefore not just a tax error; it is often a symptom of an accounting process that is overly reliant on a few key individuals.

Some cantons are free, others charge a fee: a system of fairness that is hard to decipher

Switzerland operates under a system of marked fiscal federalism. Each canton sets its own procedures, practical deadlines and reminder arrangements within its own legal framework. This autonomy allows the administration to be adapted to local circumstances, but it also creates noticeable disparities. Two taxpayers facing the same problem — a late filing, a missing document, an overburdened accountant — will not necessarily incur the same cost.

In Solothurn, the first extension until the end of July is free, but an extension until the end of November costs 30 francs. The revenue figures cited by Econostrum are significant: around 1.9 million francs from private individuals and 260,000 francs from businesses in 2024. The fact that businesses are explicitly included serves as a reminder that these practices do not affect households alone.

Conversely, Vaud and Zurich allow free extensions up to certain deadlines, provided the application is submitted on time. Econostrum notes in particular that a timely application can allow the deadline to be extended until the end of November. St Gallen, Graubünden, Lucerne and Aargau also operate a system of free deadline extensions, according to the same source.

For groups of SMEs, entrepreneurs operating in several cantons or trust companies working outside their home canton, this patchwork of rules requires strict adherence to deadlines. It is not enough to have a single internal procedure. One must know which canton charges what, from what date, via which channel and for which type of taxpayer. A request that seems routine in one canton may already incur a fee elsewhere.

The real risk begins after the reminder

Extension fees are the most obvious aspect of the issue. The greater risk arises when the tax return is not filed despite reminders. Cantonal tax authorities may then impose fines and, in problematic cases, carry out an ex officio assessment. This assessment involves estimating taxable items on the basis of the information available. It is often unfavourable to the taxpayer, as the authority does not necessarily have access to the deductions, expenses, losses or special circumstances that the return would have allowed to be documented.

For a business, an ex officio assessment can create an immediate discrepancy between the tax liability claimed and the economic reality. If the estimated profit is too high, the tax bill may tie up cash at the wrong time. Challenging the assessment subsequently takes time, requires supporting documents and means meeting new deadlines. Even when a correction is possible, the business faces an administrative burden and, at times, unnecessary strain on its cash flow.

It is also important to distinguish between filing the return and paying the tax. An extension to the filing deadline does not automatically mean that all payment deadlines are waived. According to the research report, late payment interest applies if taxes are not paid by the due date. For VAT, the rate quoted is 3.5 per cent per annum in the event of late payment. In Geneva, the report mentions late payment interest of up to 10 per cent after the deadline. These figures must be verified depending on the tax in question, the period and the specific circumstances, but they highlight a reality: the tax calendar comes at a financial cost.

In day-to-day management, this cost is not limited to fines. It can result in poorly calculated instalments, reminders that need to be dealt with, insufficient tax provisions, a delayed year-end closing, or less accurate bank reporting. A business seeking finance, preparing for a handover or negotiating with partners has every interest in presenting a well-managed tax position. Repeated delays rarely send the right signal.

Turning the tax season into a management process

The practical solution is not to rush through an incomplete tax return. For an SME, a correct tax return depends on reliable accounting: reconciled bank accounts, salaries consistent with payslips, justified expenses, fixed assets tracked, VAT checked, and shareholder current accounts properly documented. Filing quickly but incorrectly can create further problems.

The aim is rather to plan ahead. Directors should be aware of the deadline applicable to their canton and their legal form, decide early on whether an extension is necessary, and then submit the supporting documents to their accountant before the critical deadline. Where an extension incurs a fee, the cost should be treated as an avoidable expense or, at the very least, one that can be planned for. Where an extension is free of charge, it must not become an excuse to postpone the year-end closing indefinitely.

A few simple habits can make a big difference: set an internal closing schedule, set aside time for the self-employed person’s private supporting documents, check VAT accounts before preparing tax returns, document exceptional transactions, and inform the accountancy firm as soon as a deadline becomes unrealistic. The accountancy firm, for its part, can organise its clients by canton, automate reminders and prioritise electronic channels where these reduce costs.

The current debate on penalties and fees ultimately reflects a broader trend: the tax authorities expect taxpayers to adopt an increasingly structured approach to management, whilst some cantons are charging for requests for extensions. For Swiss SMEs, the best protection remains a regular accounting system. The tax deadline is not just a date in the diary: it is an indicator of management, cash flow and administrative credibility.