Nonresidents are subject to Basel-Stadt wealth tax on assets that are economically connected to the canton. In practice, this limited tax liability focuses on real estate and business assets located in Basel-Stadt, while foreign portfolios and movable property held abroad are not taxed in the canton.

This guide summarises the scope, valuation rules, and compliance requirements for the 2025 tax year for nonresident individuals with assets in Basel-Stadt.

1. Scope of Limited Tax Liability

A nonresident becomes liable for wealth tax in Basel-Stadt if they hold any of the following:

• Residential or commercial real estate situated in the canton of Basel-Stadt
• Land or development sites located within Basel-Stadt
• Permanent establishments or fixed places of business (e.g., offices, shops, hotels, restaurants) in the canton
• Business assets allocated to a Basel-Stadt branch or place of effective management

Assets outside Switzerland — such as foreign securities, overseas real estate, and non-Swiss bank accounts — are excluded from the Basel-Stadt wealth-tax base, though they may remain relevant in the country of residence for rate or reporting purposes.

2. Valuation Basis

Basel-Stadt applies cantonal valuation rules that are harmonised with federal law but implemented via its own practice:

• Real estate: Cantonal tax value (Steuerwert), generally below open-market value
• Securities and bank assets: Year-end tax value based on official federal tax value lists and foreign exchange rates
• Business assets: Book or fair value according to Swiss accounting standards, with Basel-Stadt adjustments where applicable
• Pension assets: 2nd pillar and pillar 3a pension capital is usually exempt from wealth tax until payout

The Steuerwert for real estate in Basel-Stadt reflects a fraction of market value and takes account of location, use, and building characteristics. For detailed valuation methodology in this canton, see Valuation Rules.

3. Debt Allocation

Debt allocation for nonresidents in Basel-Stadt follows the Swiss principle of economic connection combined with proportional allocation:

• Mortgages secured on Basel-Stadt property are deductible from the wealth-tax value of that property.
• Other debts are deductible only to the extent they can be economically tied to Swiss assets or allocated proportionally.
• If the taxpayer owns property in multiple Swiss cantons, total debt is allocated among cantons according to the relative taxable values of those assets.

Interest on debt is relevant for income tax and is split between jurisdictions based on Swiss-sourced assets and income, including allocation across cantons.

4. Allowances & Exemptions

Nonresident taxpayers in Basel-Stadt generally do not have access to the full range of personal allowances and deductions granted to residents. However, certain items are typically excluded from the wealth-tax base:

• Tax-exempt pension capital (occupational and pillar 3a) until withdrawal
• Normal household goods and personal belongings
• Smaller technical exemptions required under harmonised cantonal law

For nonresidents, the effective burden is mainly driven by the property’s Steuerwert, the progressive Basel-Stadt wealth tax scale, and debt allocation.

5. Double Tax Treaties

Under Switzerland’s double tax treaties, taxation of immovable property is generally assigned to the state where the property is located. As a result, Basel-Stadt retains the right to tax real estate and related business premises situated in the canton, even if the owner is resident abroad.

Relief is then usually granted in the country of residence through:

• Exemption with progression, or
• Foreign tax credit for Basel-Stadt wealth tax against home-country wealth or property taxes.

Always check the specific treaty between Switzerland and your country of residence and retain Basel-Stadt tax assessments and receipts as proof of Swiss tax paid.

6. Swiss Tax Representative

Nonresidents will usually need to provide a Swiss correspondence address or appoint a tax representative when dealing with the Basel-Stadt tax authorities.

• Swiss fiduciaries, tax advisors, or lawyers can act as authorised representatives.
• Official correspondence and assessments are issued in German.
• Using a representative helps manage deadlines, language issues, and any appeals or objections.

7. Filing & Compliance

Nonresident owners of property or business assets in Basel-Stadt file a limited Swiss tax return covering Swiss-situs income and wealth. The wealth tax portion focuses on net taxable assets situated in Basel-Stadt as at 31 December.

• Official confirmation of the property’s Steuerwert
• Mortgage and loan confirmations as of year-end
• Rental income and expense statements for let property
• Business balance sheet and asset schedules where a Basel-Stadt permanent establishment exists

Filing deadlines generally align with those for Basel-Stadt residents. Extensions are typically available upon request, often submitted via a Swiss representative.

8. Example — Nonresident City Apartment Owner

Profile: Resident of France, owns an apartment in Basel-Stadt.

• Steuerwert: CHF 1,050,000
• Mortgage balance: CHF 700,000
• Basel-Stadt multiplier / effective factor (illustrative): 1.70 (170 % of simple tax)

Step 1 — Net taxable wealth: CHF 1,050,000 − CHF 700,000 = CHF 350,000
Step 2 — Simple wealth tax (illustrative progressive rate): 3.2‰ of CHF 350,000 = CHF 1,120
Step 3 — Applying factor: CHF 1,120 × 1.70 = CHF 1,904
→ Indicative effective burden of about 0.54 % of net taxable wealth (illustrative only; actual rates depend on year and specific rules).

9. Ending Basel-Stadt Tax Liability

Wealth tax liability in Basel-Stadt normally ends when the property or business assets located in the canton are sold, transferred, or otherwise disposed of. A final limited tax return must be filed and any remaining wealth tax and property gains taxes settled.

The Basel-Stadt tax office should be notified promptly of the disposal to avoid continued assessments based on outdated ownership data.

10. Planning Insights for Nonresidents

• Obtain an estimate of the Basel-Stadt Steuerwert and effective wealth tax factor before acquiring property.
• Align mortgage structure and debt allocation with your wider cross-border wealth and estate planning.
• Review how Basel-Stadt wealth tax interacts with home-country rules and any applicable double tax treaties.
• Use a Swiss tax representative to manage filings, coordinate with your home-country advisor, and handle German-language correspondence.