
Fiduciary services for construction companies in Solothurn: the practical guide
Swiss accounting law (art. 957 ff. of the Code of Obligations) sets a precise frame, yet day-to-day practice often stays fuzzy. This guide walks through what actually matters for a business based in Solothurn.
The Swiss legal frame for fiduciary services
Responsibility for the books is personal: in an SA, organising the accounting is one of the board's non-transferable duties (art. 716a CO); in a Sàrl, the managing directors carry the same duty. Outsourcing the execution never transfers that underlying responsibility, including for a company based in Solothurn.
For fiduciary services, 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.
A Swiss SME's accounting calendar
Tax instalments are steered: too low, they set up a salty final bill; too high, they tie up cash. Adjusting them on current figures is a profitable reflex, in Solothurn as anywhere.
For a business in Solothurn, an isolated delay can be caught up; a structural delay is paid in interest, fines and stress. The difference between the two: a system, not good intentions.
Year-end closing: how the mechanics work
Accrual accounting is the technical heart of the closing: every income and every expense belongs to the year it economically concerns, regardless of the payment date. Rents paid in advance, insurance premiums straddling the date, supplier invoices arriving in January: all flow through accrual accounts.
A company in Solothurn that presents clean, punctual annual accounts gains credibility — with its bank, its suppliers and the tax administration.

Digitalising fiduciary services: what actually works
Security is part of digitalisation: named access, tested backups, encryption of sensitive data. A digital accounting file is protected like a safe — because it is one.
The winning pair for fiduciary services: a single inbox (e-mail, scan, photo) and one simple rule — no document sits more than a few days without a proposed entry.
Solothurn: what changes, what does not
Solothurn (postal code 4500, canton Solothurn) applies the same federal rules as the rest of the country: what changes in Solothurn are the cantonal counterparts — tax administration, compensation office, commercial register.
For a business in Solothurn, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Solothurn.
Frequently asked questions
Which social contributions does a Swiss employer pay?
AHV/IV/APG: 5.3% employer share (the same is withheld from the employee); unemployment insurance: 1.1% each up to CHF 148,200 a year; occupational pension (LPP) by age and plan (employer at least 50%); occupational accident insurance paid by the employer; family allowances by canton. For an employer in Solothurn, family allowances follow the canton's rates.
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 Solothurn.
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 Solothurn.
Effective VAT method or net tax rate: how to choose?
The effective method deducts actual input VAT and files quarterly; the net tax rate method applies a flat industry rate to turnover, semi-annually, with no separate input VAT deduction. The flat rate suits low-cost structures; as investments grow, the effective method usually wins again. The choice rests on the company's own figures, in Solothurn as anywhere.
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