
Fiduciary services for tradespeople in Cossonay: rules, deadlines, best practice
Fiduciary services for tradespeople in Cossonay rests on three pillars: federal law that applies across Switzerland, cantonal deadlines worth knowing, and tools that eliminate re-keying. This guide puts it all in order, fact by fact.
The Swiss legal frame for fiduciary services
In Switzerland, the duty to keep accounts stems from art. 957 ff. of the Code of Obligations. Legal entities (Sàrl, SA) and sole proprietorships with at least CHF 500,000 in revenue keep full accounts: balance sheet, income statement and notes. Below that threshold, a simplified record of income, expenses and assets is sufficient.
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 fiduciary services run entirely on digital tools — no paper binder is required.
Year-end closing: how the mechanics work
The CO's accounting principles frame the closing: regularity, prudence and consistency of presentation (art. 958c CO), on the going-concern assumption (art. 958a CO). In practice, that means valuation methods kept constant from one year to the next — and documented whenever they change.
A clean closing pays beyond the legal duty: it conditions the tax return, bank discussions and the company's value in a succession. Hidden reserves (accelerated depreciation, provisions) remain admissible within cantonal tax limits — document them systematically.
A Swiss SME's accounting calendar
Every deadline has an owner: an obligation “of everyone” is kept by no one. Naming one person per deadline family (VAT, payroll, taxes) closes the gaps.
For fiduciary services, two dates lock themselves in every year: the January salary declaration and the general meeting within six months — everything else is planned around them.

Outsource fiduciary services or keep it in-house?
Outsourcing does not exempt you from understanding: an owner who can read the balance sheet and the income statement challenges the fiduciary better — and pays for advice, not re-keying.
For fiduciary services, a quarterly 30-minute check-in with the fiduciary beats an annual marathon: questions get handled while they are small.
Cossonay: what changes, what does not
Sole proprietorship, Sàrl or SA in Cossonay: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Vaud.
For a business in Cossonay, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Vaud.
Frequently asked questions
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.
Which documents should be prepared for the year-end closing?
Bank and cash statements at the closing date, the inventory of stock and work in progress, final AHV/LPP/accident settlements, contracts signed or amended during the year, invoices straddling two years and the detail of accruals. With an up-to-date document archive, most of it is already there. The list is identical in Cossonay: the CO dictates it, not the commune.
When is entry in the commercial register mandatory?
A Sàrl and an SA only come into existence with their registration. A sole proprietorship must register from CHF 100,000 of annual revenue; below that, registration stays voluntary but adds credibility and protects the business name. Registration goes through the canton's commercial register office — for Cossonay too.
Do you need a fiduciary for fiduciary services, 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.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates fiduciary services for businesses in Cossonay: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
The application is operated in French.