
Sole proprietorship for SA companies in Obermumpf without the stress: how it works
Whether you run a Sàrl, an SA or a sole proprietorship in Obermumpf, sole proprietorship eventually lands on your desk. Here are the practical reference points — legal basis, deadlines and common pitfalls — to decide with a clear head.
Choosing the structure: Sàrl, SA or sole proprietorship
Settling in Obermumpf does not change federal law, but the canton shapes what follows: profit and capital tax rates, family allowances, possible start-up support. Comparing seriously before fixing the seat can pay off — moving a company later costs more.
First accounting reflex for sole proprietorship: open the document numbering with the very first expense, even before registration. Founding costs are deductible — if documented.
The Swiss legal frame for sole proprietorship
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. Sole proprietorship sits squarely within this frame, including for companies based in Obermumpf.
Also worth knowing: accounts may be drawn up in the currency most relevant to the business; if that is not the franc, values must additionally be stated in CHF (art. 958d para. 3 CO). Internationally active companies gain books that match their economic reality.
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 sole proprietorship: some supplies are excluded from VAT (health, education, property rental) — with no corresponding input VAT right. Qualifying revenues correctly from the start avoids surprises.

Digitalising sole proprietorship: what actually works
The classic digitalisation traps are avoidable: scanning without quality control (unreadable records), stacking disconnected tools (double entry in disguise), or neglecting access rights. One single flow from document to entry, with clear roles, beats five shiny apps.
Electronic archiving is fully recognised: Swiss bookkeeping regulation admits electronic retention of records provided integrity and readability are guaranteed for the 10 years of art. 958f CO. A paper binder is no longer an obligation — provided the archiving system is serious.
Obermumpf: what changes, what does not
Obermumpf (postal code 4324, canton Aargau) applies the same federal rules as the rest of the country: what changes in Obermumpf are the cantonal counterparts — tax administration, compensation office, commercial register.
Federal deadlines do not move in Obermumpf: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 4324 changes nothing about those rules, only the sender's address.
Frequently asked questions
What are the legal obligations for sole proprietorship 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 Obermumpf: federal law applies.
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 Obermumpf as everywhere in Switzerland.
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 Obermumpf: the CO dictates it, not the commune.
How much does sole proprietorship cost in Obermumpf?
It depends on document volume, the number of salaries and VAT complexity — no serious figure can be quoted without examining the file. Two levers cut the bill everywhere: digitised, well-filed receipts and software that prepares entries instead of having them re-keyed.
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Switch to accounting that keeps itself up to date
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