
Withholding tax for engineering firms in Commugny: the practical guide
Withholding tax for engineering firms in Commugny 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 withholding tax
AHV audits and VAT audits follow the same logic: start from the documents, trace to the entries, check consistency. A business in Commugny with a clean audit trail sails through these exercises.
For withholding tax, 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.
Outsource withholding tax or keep it in-house?
The Swiss fiduciary market is dense and governed by professional practice: industry standards, business secrecy, civil liability. Compare offers on three concrete criteria — exact scope (data entry? closing? payroll? VAT?), a named contact person, and the tools used. It prevents year-end misunderstandings.
For withholding tax, a quarterly 30-minute check-in with the fiduciary beats an annual marathon: questions get handled while they are small.
Salaries and social contributions: the rates to know
Family allowances are financed by the employer through a cantonal compensation fund — rates and amounts vary from canton to canton, including in Commugny. They come on top of the federal social insurances and appear on every payslip.
An employer in Commugny does well to fix payday on a set day of the month: funds, employees and cash flow organise around it, and withholding tax becomes routine instead of a sprint.

A Swiss SME's accounting calendar
The typical annual cycle: monthly or quarterly AHV instalments, VAT returns (quarterly under the effective method, semi-annual under the net tax rate), the final salary declaration in January, closing in the first half-year, then the tax return and the annual VAT reconciliation. Each link depends on the quality of the previous one.
For withholding tax, two dates lock themselves in every year: the January salary declaration and the general meeting within six months — everything else is planned around them.
Commugny: what changes, what does not
Commugny (postal code 1291, canton Vaud) applies the same federal rules as the rest of the country: what changes in Commugny are the cantonal counterparts — tax administration, compensation office, commercial register.
For a business in Commugny, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Vaud.
Frequently asked questions
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 Commugny too.
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 Commugny.
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 Commugny as everywhere in Switzerland.
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 Commugny, family allowances follow the canton's rates.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates withholding tax for businesses in Commugny: 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.