In Solothurn, wealth tax is filed together with the individual income tax return. The canton supports online filing via eTax Solothurn (etax.so.ch), with a fully paperless option, as well as conventional paper submission. Cantonal and communal taxes are assessed together based on combined income and wealth; municipal multipliers affect the final burden.

Filing Timeline (Typical Cycle)

1. February: Solothurn issues filing invitations and activates the current-year eTax Solothurn modules.
2. Ordinary due date (private individuals): The tax return for income and wealth is generally due by 31 March of the following year.
3. Ordinary due date (companies): Corporate tax returns are typically due by 30 June.
4. Initial extension window: An extension for individuals to 31 July is usually available free of charge upon timely request.
5. Further extension: A second extension for individuals is commonly possible up to 30 November, subject to a moderate fee; the same date often applies as ordinary deadline for certain secondarily taxable persons.
6. Assessment & billing: Provisional bills may be issued during the year; final assessments follow review of the filed return. Late payments accrue interest and may trigger reminder fees.

Always rely on the due date printed on your Solothurn tax invitation and confirm current-year rules on the cantonal tax portal.

How to File in Solothurn

1) eTax Solothurn (recommended)

• Go to eTax Solothurn (etax.so.ch) and log in using the access data provided with your filing invitation.
• Complete all income schedules and your 31 December wealth statement (assets, liabilities, allowances) in the online forms.
• Upload supporting documentation (bank and securities statements, property valuations, pension summaries, etc.) in electronic form as requested.
• Submit the return electronically. Depending on the chosen mode, the submission is usually signature-free, with any required acknowledgement handled via the portal.

2) Paper Return

• Use the official paper forms sent with your filing invitation or print the forms generated from eTax Solothurn.
• Complete the income and wealth sections, sign the return, and attach copies of supporting statements; keep originals for your own records.
• Send the signed return to the address indicated on the filing invitation or submit it via your municipal tax office, as instructed.

Extensions

If you cannot file by the ordinary due date, request an extension (Fristerstreckung) from the Solothurn tax administration. Extensions can be requested online or in writing for both individuals and companies.

• Online request: Use the canton’s online extension form linked from the Solothurn tax portal (Fristerstreckung) for a quick, paperless request.
• First extension (individuals): Requests to 31 July are generally granted automatically and free of charge if submitted on time.
• Second extension (individuals): Extensions up to around 30 November usually require a brief justification and attract a modest fee per taxpayer.
• Companies: Corporate extensions are available on request, typically beyond the ordinary 30 June deadline, subject to approval and similar fee rules.
• Request before due date: File your extension request before 31 March (or the printed deadline) to avoid reminder fees and estimated assessments.
• Penalties: Failure to file despite reminders can result in reminder fees, fines, and discretionary (estimated) assessments.

Provisional Payments, Interest & Adjustments

Solothurn issues provisional instalments based on previous assessments or estimated income and wealth. If your situation changes significantly, you may request an adjustment to these provisional amounts. After filing and review, a final assessment and bill is issued; late payments accrue interest at the cantonal rate.

• Payment references: Use the QR-bill or payment reference printed on each invoice so payments are correctly allocated.
• Partial payments: Usually permitted; keep confirmations and invoices for reconciliation with the final assessment.
• Objections (Einsprache): If you disagree with the assessment, submit a written objection within the deadline indicated on the tax notice.

Nonresidents with Solothurn-Situs Assets

Nonresidents owning Solothurn real estate or business assets (including permanent establishments) are typically subject to limited Swiss tax liability and file a limited return covering Swiss-situs income and wealth only. A Swiss correspondence address or tax representative is often required. See the Nonresident Guide.

Document Checklist (Wealth Section)

Prepare and upload/retain the following to support your 31 December wealth statement:

Annual Changes

eTax Solothurn versions, deadlines, extension rules, and communal multipliers are updated annually. Confirm the current-year requirements and due dates on the official Solothurn tax administration portal before submitting your return.