
Sàrl incorporation for architecture firms in Spreitenbach: rules, deadlines, best practice
Sàrl incorporation for architecture firms in Spreitenbach 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
A Sàrl requires CHF 20,000 of fully paid-in capital; an SA CHF 100,000 of which at least CHF 50,000 paid in. Both require a notarised deed and entry in the commercial register. A sole proprietorship arises from mere activity — registration only becomes mandatory from CHF 100,000 of annual revenue.
Settling in Spreitenbach also means thinking about insurance from incorporation: professional liability, property, business interruption — the accounts keep track of them and the closing allocates them correctly.
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 Spreitenbach.
An employer in Spreitenbach does well to fix payday on a set day of the month: funds, employees and cash flow organise around it, and Sàrl incorporation becomes routine instead of a sprint.
Digitalising Sàrl incorporation: what actually works
Artificial intelligence has changed the economics of Sàrl incorporation: 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 Sàrl incorporation
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. Sàrl incorporation sits squarely within this frame, including for companies based in Spreitenbach.
The law also settles the form: accounts may be kept in a national language or in English, on paper or electronically (art. 957a para. 5 CO). That pragmatism lets Sàrl incorporation run entirely on digital tools — no paper binder is required.
Spreitenbach: what changes, what does not
Working with a fiduciary from Spreitenbach no longer depends on geography: the documents of a business in Spreitenbach are shared online, while the canton Aargau keeps its own deadlines for the tax return.
Federal deadlines do not move in Spreitenbach: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 8957 changes nothing about those rules, only the sender's address.
Frequently asked questions
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 Spreitenbach 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 Spreitenbach as everywhere in Switzerland.
Does MyFiducia.ai work for a business based in Spreitenbach?
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 Spreitenbach manages its documents, VAT and exports exactly as anywhere in Switzerland.
Which social contributions does a Swiss employer pay?
AHV/IV/APG: 5.3% employer share (the same is withheld from the employee); unemployment insurance: 1.1% each up to CHF 148,200 a year; occupational pension (LPP) by age and plan (employer at least 50%); occupational accident insurance paid by the employer; family allowances by canton. For an employer in Spreitenbach, family allowances follow the canton's rates.
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