
Annual closing for engineering firms in Isone: rules, deadlines, best practice
Annual closing for engineering firms in Isone 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.
Year-end closing: how the mechanics work
Depreciation follows rates accepted by tax practice (property, machinery, IT): staying within those ranges avoids reassessments. Exceeding them is justified — and documented, in Isone as anywhere.
For an SME in Isone, the closing is also decision time: distributions, provisions, investments to anticipate. A file ready in February leaves time to decide; one ready in June just endures.
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 Isone.
For annual closing, year-end is prepared in October: last invoices, investment decisions, provisions to assess — December is too late to act, January is for recording.
Outsource annual closing or keep it in-house?
Outsourcing does not exempt you from understanding: an owner who can read the balance sheet and the income statement challenges the fiduciary better — and pays for advice, not re-keying.
Three signals say it is time to delegate more: missed deadlines (VAT, AHV), entries running months behind, or an owner spending evenings on receipts instead of the business. Conversely, an SME equipped with modern software can safely take day-to-day entry back in-house.

The Swiss legal frame for annual closing
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.
For annual closing, 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.
Isone: what changes, what does not
Working with a fiduciary from Isone no longer depends on geography: the documents of a business in Isone are shared online, while the canton Ticino keeps its own deadlines for the tax return.
Federal deadlines do not move in Isone: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 6810 changes nothing about those rules, only the sender's address.
Frequently asked questions
Do you need a fiduciary for annual closing, 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 Isone.
What is the difference between a limited and an ordinary audit?
The ordinary audit applies to companies exceeding, for two consecutive years, two of three thresholds: CHF 20 million balance sheet total, CHF 40 million revenue, 250 full-time positions. Others fall under the limited audit, and those with no more than ten full-time positions on annual average can opt out with all shareholders' consent. These federal thresholds do not depend on the registered seat — in Isone as anywhere.
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 Isone as anywhere.
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 Isone, family allowances follow the canton's rates.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates annual closing for businesses in Isone: 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.