
Tax advisory comparison in Cossonay: rules, deadlines, best practice
Delegate, digitalise or do it all yourself? Around tax advisory in Cossonay, every SME draws its own line. The reference points below — federal law, cantonal practice and lessons from the field — help you place the cursor well.
The Swiss legal frame for tax advisory
Swiss accounting law has been unified in the Code of Obligations since 2013: the same bookkeeping rules (art. 957a CO) and retention rules (art. 958f CO — 10 years for books, vouchers and reports) apply regardless of legal form. Tax advisory sits squarely within this frame, including for companies based in Cossonay.
For tax advisory, the classic early mistake remains mixing private and business: a dedicated bank account and documented private withdrawals eliminate half the discussions with the tax office.
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.
An SME in Cossonay that holds its calendar twelve months straight changes its position: fewer official reminders, easier extensions — and tax advisory stops being a source of worry.
Swiss VAT: rates, threshold and filings
Three rates coexist in Switzerland: 8.1% for most supplies, 2.6% for everyday essentials and 3.8% for accommodation. Businesses staying under CHF 100,000 a year are exempt from registration but may opt in voluntarily — useful to reclaim input VAT on investments.
Also useful for tax advisory: some supplies are excluded from VAT (health, education, property rental) — with no corresponding input VAT right. Qualifying revenues correctly from the start avoids surprises.

Year-end closing: how the mechanics work
The closing turns day-to-day bookkeeping into annual accounts: balance sheet, income statement and notes (art. 958 CO). Mandatory stops: accruals and deferrals, depreciation, commercially justified provisions, inventory of stock and work in progress, then VAT and AHV reconciliations.
A company in Cossonay that presents clean, punctual annual accounts gains credibility — with its bank, its suppliers and the tax administration.
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.
Federal deadlines do not move in Cossonay: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 1304 changes nothing about those rules, only the sender's address.
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.
Do you need a fiduciary for tax advisory, 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.
Can tax advisory be automated with AI?
Largely, yes: automatic document reading, posting suggestions, bank reconciliation via QR references and VAT exports. Human approval remains essential — AI prepares, the professional checks. That is exactly how MyFiducia.ai approaches tax advisory.
Which social contributions does a Swiss employer pay?
AHV/IV/APG: 5.3% employer share (the same is withheld from the employee); unemployment insurance: 1.1% each up to CHF 148,200 a year; occupational pension (LPP) by age and plan (employer at least 50%); occupational accident insurance paid by the employer; family allowances by canton. For an employer in Cossonay, family allowances follow the canton's rates.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates tax advisory for businesses in Cossonay: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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