
Sole proprietorship for law firms in Mellingen: rules, deadlines, best practice
Between VAT, social contributions and the year-end close, a Swiss SME juggles dozens of deadlines a year. This page focuses on sole proprietorship in Mellingen: what the law requires, what can be automated, and when to delegate.
Choosing the structure: Sàrl, SA or sole proprietorship
Contributions in kind (vehicle, equipment, client portfolio) are possible when founding a Sàrl or an SA, but they follow strict valuation and disclosure rules. Cash contribution remains the simple route, in Mellingen as elsewhere.
From day one, three administrative tracks open: affiliation to an AHV compensation office, review of VAT liability (CHF 100,000 threshold) and setting up the accounts. Handling sole proprietorship from the first month costs far less than reconstructing a whole year in December.
Digitalising sole proprietorship: 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 sole proprietorship: 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 sole proprietorship
AHV audits and VAT audits follow the same logic: start from the documents, trace to the entries, check consistency. A business in Mellingen with a clean audit trail sails through these exercises.
The annual accounts (art. 958 CO) consist of the balance sheet, the income statement and the notes; they must be drawn up within six months of the year-end so the general meeting can approve them. A delay here cascades into the tax return and the final social insurance settlements.

Salaries and social contributions: the rates to know
A Swiss salary reads in three columns: gross, employee social deductions, employer contributions. Confusing them distorts cost prices — and quotes from businesses in Mellingen.
For sole proprietorship, the winning mechanics are simple: one single payroll database (salaries, rates, allowances), monthly slips generated from it, and an annual declaration that is little more than a sum. Painful catch-up invoices almost always stem from scattered data.
Mellingen: what changes, what does not
Sole proprietorship, Sàrl or SA in Mellingen: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
For a business in Mellingen, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Aargau.
Frequently asked questions
Do you need a fiduciary for sole proprietorship, 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 Mellingen.
Does MyFiducia.ai work for a business based in Mellingen?
Yes: the platform runs online, the rules applied are federal (VAT, CO, AHV), and the file can be shared with any fiduciary. A business in Mellingen manages its documents, VAT and exports exactly as anywhere in Switzerland.
What are the current Swiss VAT rates?
Since 1 January 2024: 8.1% (standard), 2.6% (reduced — for example food and medicines) and 3.8% (accommodation). Returns must be filed and paid within 60 days after the period ends (quarterly under the effective method, semi-annually under the net tax rate method). These federal rates apply unchanged in Mellingen.
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 Mellingen too.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates sole proprietorship for businesses in Mellingen: 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.