Smiling team looking at a laptop

SME tax return required documents in Lenzburg: rules, deadlines, best practice

Swiss accounting law (art. 957 ff. of the Code of Obligations) sets a precise frame, yet day-to-day practice often stays fuzzy. This guide walks through what actually matters for a business based in Lenzburg.

The Swiss legal frame for SME tax return

In Switzerland, the duty to keep accounts stems from art. 957 ff. of the Code of Obligations. Legal entities (Sàrl, SA) and sole proprietorships with at least CHF 500,000 in revenue keep full accounts: balance sheet, income statement and notes. Below that threshold, a simplified record of income, expenses and assets is sufficient.

One simple principle drives SME tax return: 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.

Outsource SME tax return or keep it in-house?

The Swiss fiduciary market is dense and governed by professional practice: industry standards, business secrecy, civil liability. Compare offers on three concrete criteria — exact scope (data entry? closing? payroll? VAT?), a named contact person, and the tools used. It prevents year-end misunderstandings.

For SME tax return, the internal-external duo works when both sides see the same file: same entries, same documents, same deadlines. Misunderstandings are born from parallel copies.

A Swiss SME's accounting calendar

Three families of deadlines shape the year: federal (VAT within 60 days, salary declaration in January), cantonal (tax return, extensions depending on the canton, including in Lenzburg) and internal (closing, general meeting within six months). Mixing them up is the leading cause of delays.

An SME in Lenzburg that holds its calendar twelve months straight changes its position: fewer official reminders, easier extensions — and SME tax return stops being a source of worry.

Collaborative desk with laptops and documents, top view

Year-end closing: how the mechanics work

The closing turns day-to-day bookkeeping into annual accounts: balance sheet, income statement and notes (art. 958 CO). Mandatory stops: accruals and deferrals, depreciation, commercially justified provisions, inventory of stock and work in progress, then VAT and AHV reconciliations.

For SME tax return, a closing checklist reused every year transforms the exercise: same steps, same checks, same documents — only the year changes.

Lenzburg: what changes, what does not

Working with a fiduciary from Lenzburg no longer depends on geography: the documents of a business in Lenzburg are shared online, while the canton Aargau keeps its own deadlines for the tax return.

Federal deadlines do not move in Lenzburg: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5600 changes nothing about those rules, only the sender's address.

Frequently asked questions

What are the legal obligations for SME tax return 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 Lenzburg: federal law applies.

Which documents should be prepared for the year-end closing?

Bank and cash statements at the closing date, the inventory of stock and work in progress, final AHV/LPP/accident settlements, contracts signed or amended during the year, invoices straddling two years and the detail of accruals. With an up-to-date document archive, most of it is already there. The list is identical in Lenzburg: the CO dictates it, not the commune.

How much does SME tax return cost in Lenzburg?

It depends on document volume, the number of salaries and VAT complexity — no serious figure can be quoted without examining the file. Two levers cut the bill everywhere: digitised, well-filed receipts and software that prepares entries instead of having them re-keyed.

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 Lenzburg too.

Also worth reading

In neighbouring municipalities

Switch to accounting that keeps itself up to date

MyFiducia.ai automates SME tax return for businesses in Lenzburg: 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.