
Sole proprietorship for construction companies in Saint-Martin (VS): what every SME should know
Sole proprietorship for construction companies in Saint-Martin (VS) raises the same questions for most Swiss SME owners: which obligations apply, which deadlines are running, which documents to prepare. This page covers the federal rules in force — without unnecessary jargon.
Choosing the structure: Sàrl, SA or sole proprietorship
Chronologically, incorporation follows a precise thread: choose the form and the company name, pay the capital into an escrow account (Sàrl/SA), notarised deed, entry in the commercial register, then AHV affiliation and the VAT check. The Confederation's online desk (EasyGov) walks founders through these steps.
Sole proprietorship 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 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.
An SME in Saint-Martin (VS) that digitalises gains owner time first: less filing, fewer “where is that receipt?” questions, more attention to the trade — that is the real return of sole proprietorship.
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 Saint-Martin (VS) with a clean audit trail sails through these exercises.
Art. 957a CO requires complete, truthful and systematic recording of transactions, each entry backed by a supporting document. For sole proprietorship, that means in practice: no movement without a receipt, and an audit trail that can be reconstructed at any time — including during a VAT or AHV inspection.

Swiss VAT: rates, threshold and filings
Registration happens with the Federal Tax Administration and yields a VAT number based on the business identifier (format CHE-xxx.xxx.xxx VAT). From then on, every invoice must state that number, the rate applied and the tax amount — three details sole proprietorship should lock down from day one to avoid retroactive fixes.
A business in Saint-Martin (VS) that crosses the threshold mid-year must register without delay: retroactive registration with interest always costs more than signing up on time.
Saint-Martin (VS): what changes, what does not
Working with a fiduciary from Saint-Martin (VS) no longer depends on geography: the documents of a business in Saint-Martin (VS) are shared online, while the canton Valais keeps its own deadlines for the tax return.
For a business in Saint-Martin (VS), that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Valais.
Frequently asked questions
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.
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 Saint-Martin (VS) too.
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 Saint-Martin (VS): federal law applies.
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 Saint-Martin (VS) as anywhere.
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In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates sole proprietorship for businesses in Saint-Martin (VS): AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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