
Tax advisory for construction companies in Duillier without the stress: how it works
Whether you run a Sàrl, an SA or a sole proprietorship in Duillier, tax advisory eventually lands on your desk. Here are the practical reference points — legal basis, deadlines and common pitfalls — to decide with a clear head.
The Swiss legal frame for tax advisory
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. Tax advisory sits squarely within this frame, including for companies based in Duillier.
Art. 957a CO requires complete, truthful and systematic recording of transactions, each entry backed by a supporting document. For tax advisory, 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.
A Swiss SME's accounting calendar
Tax instalments are steered: too low, they set up a salty final bill; too high, they tie up cash. Adjusting them on current figures is a profitable reflex, in Duillier as anywhere.
For tax advisory, two dates lock themselves in every year: the January salary declaration and the general meeting within six months — everything else is planned around them.
Swiss VAT: rates, threshold and filings
Since 1 January 2024, Swiss VAT rates are 8.1% (standard), 2.6% (reduced — food, books, medicines) and 3.8% (accommodation). Registration becomes mandatory from CHF 100,000 of worldwide annual turnover. For tax advisory, step one is therefore checking the threshold and choosing the right reporting method.
Also useful for tax advisory: some supplies are excluded from VAT (health, education, property rental) — with no corresponding input VAT right. Qualifying revenues correctly from the start avoids surprises.

Year-end closing: how the mechanics work
The order of operations matters: reconciliations first (bank, cash, receivables, payables), then the closing entries, finally the VAT and AHV consistency checks. Reversing the order means starting over.
A well-ordered closing file speeds everything up: bank statements at the closing date, a signed inventory, final AHV/LPP/accident settlements, new or amended contracts, and support for the accruals. Tax advisory in Duillier then finishes in days, not weeks.
Duillier: what changes, what does not
Sole proprietorship, Sàrl or SA in Duillier: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Vaud.
For a business in Duillier, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Vaud.
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 Duillier as anywhere.
How long must records related to tax advisory 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 Duillier can therefore archive fully digitally.
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 Duillier too.
What are the legal obligations for tax advisory 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 Duillier: federal law applies.
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