
Everything that matters about withholding tax for e-commerce in Aristau
Withholding tax for e-commerce 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.
The Swiss legal frame for withholding tax
Three documents summarise the health of a Swiss business: the balance sheet (what it owns), the income statement (what it earns) and the notes (what else you should know). All the work of withholding tax converges on those three pages, in Aristau too.
The law also settles the form: accounts may be kept in a national language or in English, on paper or electronically (art. 957a para. 5 CO). That pragmatism lets withholding tax run entirely on digital tools — no paper binder is required.
A Swiss SME's accounting calendar
The typical annual cycle: monthly or quarterly AHV instalments, VAT returns (quarterly under the effective method, semi-annual under the net tax rate), the final salary declaration in January, closing in the first half-year, then the tax return and the annual VAT reconciliation. Each link depends on the quality of the previous one.
Handing deadline monitoring to a tool is no luxury: automatic reminders, a status per obligation, and an “all green” view that clears the mind. What matters is not who ticks the box — but that the box exists and everyone can see it.
Outsource withholding tax or keep it in-house?
Splitting roles clearly avoids duplication: the company captures documents and approves payments; the fiduciary checks postings, closes the year and defends the file before the authorities. Each side does what it does best — and nobody keys the same invoice twice.
For withholding tax, the internal-external duo works when both sides see the same file: same entries, same documents, same deadlines. Misunderstandings are born from parallel copies.

Salaries and social contributions: the rates to know
Every salary paid in Switzerland triggers joint contributions: AHV/IV/APG at 10.6% in total, i.e. 5.3% borne by the employer and 5.3% withheld from the employee; unemployment insurance at 2.2% (1.1% each) up to CHF 148,200 of annual salary. Add occupational pension (LPP credits of 7 to 18% of the coordinated salary depending on age, employer at least 50%), accident insurance (occupational accidents paid by the employer) and family allowances.
An employer in Aristau does well to fix payday on a set day of the month: funds, employees and cash flow organise around it, and withholding tax becomes routine instead of a sprint.
Aristau: what changes, what does not
Aristau (postal code 5628, canton Aargau) applies the same federal rules as the rest of the country: what changes in Aristau are the cantonal counterparts — tax administration, compensation office, commercial register.
Federal deadlines do not move in Aristau: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5628 changes nothing about those rules, only the sender's address.
Frequently asked questions
What is simplified bookkeeping and who can use it?
Sole proprietorships and partnerships under CHF 500,000 of revenue may limit themselves to recording income, expenses and assets (art. 957 para. 2 CO). Once over the threshold — or upon founding a Sàrl or an SA — full accounts with balance sheet, income statement and notes become mandatory. The CHF 500,000 threshold is assessed the same way in Aristau.
How long must records related to withholding tax 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.
Do you need a fiduciary for withholding tax, 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.
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.
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