
Withholding tax automation in Thônex without the stress: how it works
Whether you run a Sàrl, an SA or a sole proprietorship in Thônex, withholding tax 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 withholding tax
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. Withholding tax sits squarely within this frame, including for companies based in Thônex.
For withholding tax, the classic early mistake remains mixing private and business: a dedicated bank account and documented private withdrawals eliminate half the discussions with the tax office.
Digitalising withholding tax: what actually works
Digitising does not mean hoarding PDFs: without the document-entry link, a digital file is as opaque as a box of archives — true in Thônex as everywhere.
The winning pair for withholding tax: a single inbox (e-mail, scan, photo) and one simple rule — no document sits more than a few days without a proposed entry.
Outsource withholding tax or keep it in-house?
The scope goes down in writing: who enters data, who approves payments, who answers the tax office, who keeps the originals. Every “we'll see” at the start becomes a December misunderstanding — in Thônex as elsewhere.
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.

Salaries and social contributions: the rates to know
The salary certificate is an official tax document: it feeds the employee's tax return and serves as the reference in AHV and tax audits. Issued once a year, it must match payroll accounting and the declaration to the compensation office to the centime.
For withholding tax, the monthly payslip is only the visible part: instalments to the funds, annual settlements and certificates form the real cycle, January to January.
Thônex: what changes, what does not
Sole proprietorship, Sàrl or SA in Thônex: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Geneva.
Federal deadlines do not move in Thônex: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 1226 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 Thônex.
What are the legal obligations for withholding tax 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 Thônex: federal law applies.
Does MyFiducia.ai work for a business based in Thônex?
Yes: the platform runs online, the rules applied are federal (VAT, CO, AHV), and the file can be shared with any fiduciary. A business in Thônex manages its documents, VAT and exports exactly as anywhere in Switzerland.
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 Thônex can therefore archive fully digitally.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates withholding tax for businesses in Thônex: 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.