
Tax advisory for law firms in Wisen (SO) without the stress: how it works
Between VAT, social contributions and the year-end close, a Swiss SME juggles dozens of deadlines a year. This page focuses on tax advisory in Wisen (SO): what the law requires, what can be automated, and when to delegate.
The Swiss legal frame for tax advisory
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. Tax advisory sits squarely within this frame, including for companies based in Wisen (SO).
Also worth knowing: accounts may be drawn up in the currency most relevant to the business; if that is not the franc, values must additionally be stated in CHF (art. 958d para. 3 CO). Internationally active companies gain books that match their economic reality.
Outsource tax advisory or keep it in-house?
Responsibility stays with the client: the fiduciary executes with care, but the signed accounts bind the company. Understanding what you sign is not optional.
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.
A Swiss SME's accounting calendar
An accounting calendar only lives if it is shared: owner, in-house bookkeeper and fiduciary must see the same deadlines and the same status — the rule holds for every SME in Wisen (SO).
For tax advisory, year-end is prepared in October: last invoices, investment decisions, provisions to assess — December is too late to act, January is for recording.

Swiss VAT: rates, threshold and filings
Registration happens with the Federal Tax Administration and yields a VAT number based on the business identifier (format CHE-xxx.xxx.xxx VAT). From then on, every invoice must state that number, the rate applied and the tax amount — three details tax advisory should lock down from day one to avoid retroactive fixes.
For businesses in Wisen (SO), VAT is in practice the most audited tax: punctual returns consistent with the books markedly reduce the odds of a deep audit of tax advisory.
Wisen (SO): what changes, what does not
Wisen (SO) (postal code 4634, canton Solothurn) applies the same federal rules as the rest of the country: what changes in Wisen (SO) are the cantonal counterparts — tax administration, compensation office, commercial register.
For a business in Wisen (SO), that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Solothurn.
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 Wisen (SO).
What are the legal obligations for tax advisory 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 Wisen (SO): federal law applies.
Can tax advisory be automated with AI?
Largely, yes: automatic document reading, posting suggestions, bank reconciliation via QR references and VAT exports. Human approval remains essential — AI prepares, the professional checks. That is exactly how MyFiducia.ai approaches tax advisory.
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 Wisen (SO): the CO dictates it, not the commune.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates tax advisory for businesses in Wisen (SO): 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.