
SME tax return checklist in Cossonay: the practical guide
SME tax return checklist in Cossonay raises the same questions for most Swiss SME owners: which obligations apply, which deadlines are running, which documents to prepare. This page covers the federal rules in force — without unnecessary jargon.
The Swiss legal frame for SME tax return
Whether a business sits in Cossonay or elsewhere in Switzerland, the same federal law applies — one of the strengths of the Swiss system for SME tax return. Cantonal differences concentrate on taxation (rates, filing deadlines); bookkeeping itself follows art. 957 ff. CO everywhere.
The law also settles the form: accounts may be kept in a national language or in English, on paper or electronically (art. 957a para. 5 CO). That pragmatism lets SME tax return run entirely on digital tools — no paper binder is required.
A Swiss SME's accounting calendar
Extensions exist and can be requested: cantonal deadlines for the tax return, deferral of the VAT filing on a reasoned request. But an extension does not stop interest: on VAT, default interest runs from the ordinary due date even when more time has been granted.
For SME tax return, deadline discipline is worth real money: default interest on late VAT, AHV adjustments, tax fines. A shared deadline calendar — fed by up-to-date figures — remains the simplest safeguard.
Year-end closing: how the mechanics work
The closing is prepared all year long: a monthly bank reconciliation and accruals tracked as you go turn the year-end into a formality, for businesses in Cossonay too.
The notes complete the figures: valuation principles, liabilities towards pension institutions, contingent liabilities, or the number of full-time positions. Careful notes reduce questions from the auditor and the banks.

Outsource SME tax return or keep it in-house?
The scope goes down in writing: who enters data, who approves payments, who answers the tax office, who keeps the originals. Every “we'll see” at the start becomes a December misunderstanding — in Cossonay as elsewhere.
In Cossonay, as everywhere, the right collaboration rhythm follows the activity: monthly for payroll and data entry, quarterly for VAT, yearly for the closing and tax advice.
Cossonay: what changes, what does not
Cossonay (postal code 1304, canton Vaud) applies the same federal rules as the rest of the country: what changes in Cossonay are the cantonal counterparts — tax administration, compensation office, commercial register.
Cossonay requires no special bookkeeping: the Code of Obligations applies at postal code 1304 as everywhere else, and a well-kept digital file transfers smoothly to any auditor in the canton.
Frequently asked questions
Do you need a fiduciary for SME tax return, or can you do it yourself?
Both are defensible. Below CHF 500,000 of revenue, a sole proprietorship may keep simplified accounts itself. As soon as payroll, VAT and a closing with tax stakes are involved, professional support prevents mistakes that cost more than the fees. With a shared platform, the fiduciary does not even need to be in Cossonay.
What is simplified bookkeeping and who can use it?
Sole proprietorships and partnerships under CHF 500,000 of revenue may limit themselves to recording income, expenses and assets (art. 957 para. 2 CO). Once over the threshold — or upon founding a Sàrl or an SA — full accounts with balance sheet, income statement and notes become mandatory. The CHF 500,000 threshold is assessed the same way in Cossonay.
What are the legal obligations for SME tax return in Switzerland?
The foundation is the Code of Obligations: proper bookkeeping (art. 957a CO), annual accounts (balance sheet, income statement, notes) and 10-year retention of books and records (art. 958f CO). VAT applies from CHF 100,000 of turnover, and social insurance settlements from the first employee. Nothing is different in Cossonay: federal law applies.
When must a business register for VAT?
As soon as its worldwide annual turnover reaches CHF 100,000 (CHF 250,000 for non-profit sports or cultural associations). Below that, voluntary registration remains possible and often makes sense to reclaim input VAT on investments. The threshold is federal: it applies in Cossonay as everywhere in Switzerland.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
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