
Sole proprietorship fees in Sommeri: the practical guide
Sole proprietorship fees in Sommeri 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
Partners from day one? A shareholders' agreement settles what the articles do not: exit, deadlock, valuation. Signing it while everything is fine costs an evening; negotiating it in a crisis costs the company.
A Sàrl and an SA must also appoint an auditor, unless they opt out (no more than ten full-time positions on annual average and unanimous shareholder consent). Many young companies start without one, then appoint an auditor when growth or investors demand it.
Salaries and social contributions: the rates to know
Two of these contributions are set by law: AHV/IV/APG at 5.3% and unemployment at 1.1%, both payable by the employer. The others — LPP, accident insurance, possibly daily sickness benefits and family allowances — depend on the insurer, the industry and the pension plan. The total surcharge usually falls between 12 and 20% of gross pay, and employee deductions between 10 and 15%: these are orders of magnitude, not statutory rates.
For sole proprietorship, the gap between agreed gross and paid net surprises every new employer: simulate it BEFORE hiring to avoid misunderstandings with the future employee.
Digitalising sole proprietorship: what actually works
Artificial intelligence has changed the economics of sole proprietorship: automatic invoice reading reaches recognition rates that make manual entry marginal, and posting suggestions learn from corrections. The accountant does not disappear — the job shifts from data entry to control and advice.
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.

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 Sommeri.
One simple principle drives sole proprietorship: every franc in or out must be explainable by a document, an entry and an account. All of Swiss accounting law fits inside that traceability requirement.
Sommeri: what changes, what does not
Sole proprietorship, Sàrl or SA in Sommeri: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Thurgau.
For a business in Sommeri, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Thurgau.
Frequently asked questions
Does MyFiducia.ai work for a business based in Sommeri?
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 Sommeri manages its documents, VAT and exports exactly as anywhere in Switzerland.
Can sole proprietorship 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 sole proprietorship.
What is the difference between a limited and an ordinary audit?
The ordinary audit applies to companies exceeding, for two consecutive years, two of three thresholds: CHF 20 million balance sheet total, CHF 40 million revenue, 250 full-time positions. Others fall under the limited audit, and those with no more than ten full-time positions on annual average can opt out with all shareholders' consent. These federal thresholds do not depend on the registered seat — in Sommeri as anywhere.
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 Sommeri as everywhere in Switzerland.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates sole proprietorship for businesses in Sommeri: 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.