
Tax advisory for architecture firms in Seon: what every SME should know
Tax advisory for architecture firms in Seon rests on three pillars: federal law that applies across Switzerland, cantonal deadlines worth knowing, and tools that eliminate re-keying. This guide puts it all in order, fact by fact.
The Swiss legal frame for tax advisory
AHV audits and VAT audits follow the same logic: start from the documents, trace to the entries, check consistency. A business in Seon with a clean audit trail sails through these exercises.
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 tax advisory run entirely on digital tools — no paper binder is required.
Outsource tax advisory or keep it in-house?
A fiduciary's cost depends first on the quality of the data received: digitised, filed, reconciled documents are processed fast; a box of loose receipts is billed by the hour. Improving the internal preparation of tax advisory lowers fees more surely than any negotiation.
In Seon, as everywhere, the right collaboration rhythm follows the activity: monthly for payroll and data entry, quarterly for VAT, yearly for the closing and tax advice.
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 Seon) and internal (closing, general meeting within six months). Mixing them up is the leading cause of delays.
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.

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 Seon too.
The notes complete the figures: valuation principles, liabilities towards pension institutions, contingent liabilities, or the number of full-time positions. Careful notes reduce questions from the auditor and the banks.
Seon: what changes, what does not
Sole proprietorship, Sàrl or SA in Seon: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
Federal deadlines do not move in Seon: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5703 changes nothing about those rules, only the sender's address.
Frequently asked questions
How long must records related to tax advisory 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 Seon can therefore archive fully digitally.
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 Seon: the CO dictates it, not the commune.
How much does tax advisory cost in Seon?
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 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 Seon as everywhere in Switzerland.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates tax advisory for businesses in Seon: 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.