
Everything that matters about annual closing for engineering firms in Aristau
Annual closing for engineering firms in Aristau 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.
Year-end closing: how the mechanics work
The closing is prepared all year long: a monthly bank reconciliation and accruals tracked as you go turn the year-end into a formality, for businesses in Aristau too.
The timetable is tight: accounts drawn up and approved by the general meeting within six months of the year-end. For annual closing, chasing missing documents from January (bank statements, contracts, insurance settlements) avoids the last-minute sprint and auditor reservations.
Outsource annual closing or keep it in-house?
Outsourcing does not exempt you from understanding: an owner who can read the balance sheet and the income statement challenges the fiduciary better — and pays for advice, not re-keying.
A clear mandate agreement states who does what by when: document handover, posting deadlines, filing calendar, and responsibility for delays. A shared platform (same data, same document archive) between the company and its fiduciary eliminates binder ping-pong and duplicate entry.
The Swiss legal frame for annual closing
Whether a business sits in Aristau or elsewhere in Switzerland, the same federal law applies — one of the strengths of the Swiss system for annual closing. Cantonal differences concentrate on taxation (rates, filing deadlines); bookkeeping itself follows art. 957 ff. CO everywhere.
The annual accounts (art. 958 CO) consist of the balance sheet, the income statement and the notes; they must be drawn up within six months of the year-end so the general meeting can approve them. A delay here cascades into the tax return and the final social insurance settlements.

A well-structured SME chart of accounts
The same chart serves three readings: accounting (accuracy), tax (accepted adjustments) and management (margins by activity). Modern software produces all three views without double entry.
For a business in Aristau, comparability over time beats sophistication: a chart stable for five years beats a “perfect” one rebuilt every year. Banks and the tax administration read year-on-year movements first.
Aristau: what changes, what does not
Sole proprietorship, Sàrl or SA in Aristau: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
For a business in Aristau, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Aargau.
Frequently asked questions
What are the legal obligations for annual closing 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 Aristau: federal law applies.
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 Aristau as everywhere 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 Aristau, family allowances follow the canton's rates.
How long must records related to annual closing 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 Aristau can therefore archive fully digitally.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates annual closing for businesses in Aristau: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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