
SME tax return for opticians in Aristau: the practical guide
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 Aristau.
The Swiss legal frame for SME tax return
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. SME tax return sits squarely within this frame, including for companies based in Aristau.
The good news: the Swiss frame is stable and predictable. Structure SME tax return once — chart of accounts, document flow, calendar — and the same organisation pays off for years.
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 Aristau) and internal (closing, general meeting within six months). Mixing them up is the leading cause of delays.
An SME in Aristau 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.
Swiss VAT: rates, threshold and filings
Taxable consideration is not limited to the invoiced price: barter, set-offs and benefits in kind count too. The safe reflex: every economic advantage received is documented and qualified.
Also useful for SME tax return: some supplies are excluded from VAT (health, education, property rental) — with no corresponding input VAT right. Qualifying revenues correctly from the start avoids surprises.

Outsource SME tax return or keep it in-house?
A good test before choosing: ask the fiduciary HOW it wants to receive the documents. A precise answer (formats, frequency, platform) says more than any brochure — including in Aristau.
For SME tax return, a quarterly 30-minute check-in with the fiduciary beats an annual marathon: questions get handled while they are small.
Aristau: what changes, what does not
Working with a fiduciary from Aristau no longer depends on geography: the documents of a business in Aristau are shared online, while the canton Aargau keeps its own deadlines for the tax return.
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
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 Aristau: the CO dictates it, not the commune.
How much does SME tax return cost in Aristau?
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 Aristau too.
Do you need a fiduciary for SME tax return, 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 Aristau.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates SME tax return for businesses in Aristau: 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.