
Sole proprietorship for engineering firms in Cartigny: what every SME should know
Whether you run a Sàrl, an SA or a sole proprietorship in Cartigny, 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
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 Cartigny as elsewhere.
On taxes, corporate profit bears direct federal tax at 8.5% (statutory rate) plus cantonal and communal tax — the total effective burden varies markedly between cantons. A realistic business plan and accounts kept from the start make bank credit noticeably easier.
Swiss VAT: rates, threshold and filings
Charging VAT is not a matter of style: the number, the correct rate, the tax amount — the tax administration checks the form as closely as the substance, including at SMEs in Cartigny.
A business in Cartigny that crosses the threshold mid-year must register without delay: retroactive registration with interest always costs more than signing up on time.
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 Cartigny. They come on top of the federal social insurances and appear on every payslip.
An employer in Cartigny does well to fix payday on a set day of the month: funds, employees and cash flow organise around it, and sole proprietorship becomes routine instead of a sprint.

Digitalising sole proprietorship: what actually works
Digitising does not mean hoarding PDFs: without the document-entry link, a digital file is as opaque as a box of archives — true in Cartigny as everywhere.
For sole proprietorship, migrating history must not block the start: begin on day one of the current financial year and import the history later if needed.
Cartigny: what changes, what does not
Sole proprietorship, Sàrl or SA in Cartigny: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Geneva.
Cartigny requires no special bookkeeping: the Code of Obligations applies at postal code 1236 as everywhere else, and a well-kept digital file transfers smoothly to any auditor in the canton.
Frequently asked questions
How long must records related to sole proprietorship be kept?
Ten years from the end of the financial year concerned (art. 958f CO). Electronic retention is permitted if the integrity and readability of the records are guaranteed — a serious digital archive validly replaces paper binders. A business in Cartigny can therefore archive fully digitally.
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 Cartigny.
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 Cartigny as anywhere.
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 Cartigny too.
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