
Social security contributions for construction companies in Seewen: rules, deadlines, best practice
Delegate, digitalise or do it all yourself? Around social security contributions in Seewen, every SME draws its own line. The reference points below — federal law, cantonal practice and lessons from the field — help you place the cursor well.
The Swiss legal frame for social security contributions
In Switzerland, the duty to keep accounts stems from art. 957 ff. of the Code of Obligations. Legal entities (Sàrl, SA) and sole proprietorships with at least CHF 500,000 in revenue keep full accounts: balance sheet, income statement and notes. Below that threshold, a simplified record of income, expenses and assets is sufficient.
Art. 957a CO requires complete, truthful and systematic recording of transactions, each entry backed by a supporting document. For social security contributions, that means in practice: no movement without a receipt, and an audit trail that can be reconstructed at any time — including during a VAT or AHV inspection.
Outsource social security contributions or keep it in-house?
The Swiss fiduciary market is dense and governed by professional practice: industry standards, business secrecy, civil liability. Compare offers on three concrete criteria — exact scope (data entry? closing? payroll? VAT?), a named contact person, and the tools used. It prevents year-end misunderstandings.
A business in Seewen can combine the models: internal day-to-day entry, monthly external supervision, closing and taxes with the specialist — social security contributions splits very well.
Salaries and social contributions: the rates to know
Expense claims are payroll in the broad sense: actual reimbursements against receipts, or flat rates approved by the cantonal tax office in an expense policy. Without a clear rule, every reimbursement becomes a debate.
For social security contributions, the practical challenge is the calendar: AHV instalments during the year, salary declaration to the compensation office in January, salary certificates for staff, and final LPP/accident settlements. A clean payroll base avoids unpleasant catch-up invoices.

Digitalising social security contributions: 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 Seewen as everywhere.
An SME in Seewen that digitalises gains owner time first: less filing, fewer “where is that receipt?” questions, more attention to the trade — that is the real return of social security contributions.
Seewen: what changes, what does not
Working with a fiduciary from Seewen no longer depends on geography: the documents of a business in Seewen are shared online, while the canton Solothurn keeps its own deadlines for the tax return.
Seewen requires no special bookkeeping: the Code of Obligations applies at postal code 4206 as everywhere else, and a well-kept digital file transfers smoothly to any auditor in the canton.
Frequently asked questions
Do you need a fiduciary for social security contributions, 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 Seewen.
What are the legal obligations for social security contributions 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 Seewen: federal law applies.
What are the current Swiss VAT rates?
Since 1 January 2024: 8.1% (standard), 2.6% (reduced — for example food and medicines) and 3.8% (accommodation). Returns must be filed and paid within 60 days after the period ends (quarterly under the effective method, semi-annually under the net tax rate method). These federal rates apply unchanged in Seewen.
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 Seewen.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates social security contributions for businesses in Seewen: 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.