
Bookkeeping for construction companies in Derendingen: rules, deadlines, best practice
Whether you run a Sàrl, an SA or a sole proprietorship in Derendingen, bookkeeping 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 bookkeeping
AHV audits and VAT audits follow the same logic: start from the documents, trace to the entries, check consistency. A business in Derendingen with a clean audit trail sails through these exercises.
One simple principle drives bookkeeping: 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.
A Swiss SME's accounting calendar
January: salary declaration to the compensation office and salary certificates. End of February, May, August, November: quarterly VAT returns (effective method), each to be filed and paid within 60 days after the quarter ends. Within six months of year-end: approved annual accounts. Then: the tax return under cantonal deadlines, with extensions possible.
For bookkeeping, two dates lock themselves in every year: the January salary declaration and the general meeting within six months — everything else is planned around them.
A well-structured SME chart of accounts
Shareholder current accounts demand strict hygiene: every private withdrawal documented, interest at the rates accepted by the tax administration, and a clean-up at closing.
In an SME in Derendingen, the chart of accounts is also a delegation tool: clear posting rules let a non-accountant prepare most entries without error.

Outsource bookkeeping or keep it in-house?
Outsourcing bookkeeping to a fiduciary frees up time and secures compliance; keeping it in-house preserves a continuous view and costs less in fees. The best answer is often hybrid: the company captures and digitises as it goes, the fiduciary supervises, closes the books and represents the company before the authorities.
Changing fiduciary is not a drama: the accounting data belongs to the company, and a clean export (entries, chart of accounts, linked documents) allows a transition at year-end. A provider who locks in a client's data says a lot about how it works.
Derendingen: what changes, what does not
Derendingen (postal code 4552, canton Solothurn) applies the same federal rules as the rest of the country: what changes in Derendingen are the cantonal counterparts — tax administration, compensation office, commercial register.
For a business in Derendingen, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Solothurn.
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 Derendingen as anywhere.
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 Derendingen, family allowances follow the canton's rates.
How long must records related to bookkeeping 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 Derendingen can therefore archive fully digitally.
Do you need a fiduciary for bookkeeping, 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 Derendingen.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates bookkeeping for businesses in Derendingen: 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.