
SA incorporation for law firms in Winznau: rules, deadlines, best practice
SA incorporation for law firms in Winznau 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.
Choosing the structure: Sàrl, SA or sole proprietorship
The choice of legal form turns on three axes: liability (limited to capital for Sàrl and SA, unlimited for the sole trader), taxation (economic double taxation of company profit and dividends versus direct income taxation) and pensions (the employee of their own Sàrl is subject to mandatory LPP; the self-employed insure voluntarily).
SA incorporation starts on day one: founding capital, notary and register fees are the first entries. Opening a separate business bank account immediately — even for a sole proprietorship — saves hours of sorting private from business.
Digitalising SA incorporation: what actually works
Access for the fiduciary, the auditor and employees is set by roles: view, enter, approve, close. Well-set rights protect the data and speed up collaboration.
The winning pair for SA incorporation: a single inbox (e-mail, scan, photo) and one simple rule — no document sits more than a few days without a proposed entry.
The Swiss legal frame for SA incorporation
Three documents summarise the health of a Swiss business: the balance sheet (what it owns), the income statement (what it earns) and the notes (what else you should know). All the work of SA incorporation converges on those three pages, in Winznau too.
For SA incorporation, 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.

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 Winznau. They come on top of the federal social insurances and appear on every payslip.
An employer in Winznau does well to fix payday on a set day of the month: funds, employees and cash flow organise around it, and SA incorporation becomes routine instead of a sprint.
Winznau: what changes, what does not
Sole proprietorship, Sàrl or SA in Winznau: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Solothurn.
For a business in Winznau, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Solothurn.
Frequently asked questions
Do you need a fiduciary for SA incorporation, 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 Winznau.
What are the legal obligations for SA incorporation 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 Winznau: federal law applies.
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 Winznau, family allowances follow the canton's rates.
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 Winznau.
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MyFiducia.ai automates SA incorporation for businesses in Winznau: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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