Solothurn Corporate & Capital Tax Rates
Last updated: 09 Dec 2025
Solothurn Corporate & Capital Tax Rates
How corporate profit and capital tax rates work in the Canton of Solothurn: combined corporate income tax burden of around 15.3% in the city of Solothurn, capital tax of about 0.17% on equity with crediting of profit tax, minimum capital tax, STAF instruments such as the R&D super-deduction and patent box, approximate effective combined burdens (including federal tax), and tools to model the tax load for companies in Solothurn.
Overview
Companies in Solothurn pay a combination of:
- Cantonal/communal profit tax on taxable profit;
- Cantonal/communal capital tax on taxable equity; and
- Direct federal corporate income tax on profit.
For capital companies and cooperatives (Kapitalgesellschaften und Genossenschaften), Solothurn has implemented a competitive ordinary regime in the context of the Swiss corporate tax reform (STAF). Since 2022, the combined ordinary corporate income tax burden in the city of Solothurn is approximately 15.3% of profit before tax (including federal, cantonal and communal tax).
Capital tax is levied as a percentage of taxable equity. In the city of Solothurn, the combined capital tax burden for ordinary companies is around 0.17% of equity. Profit tax is credited against capital tax, so that capital tax effectively acts as a minimum tax in low-profit or loss years.
As part of its STAF implementation, Solothurn also introduced a 50% R&D super-deduction on qualifying research and development expenses and a patent box for income from qualifying patents and comparable rights, subject to an overall relief cap.
This page summarises the core profit and capital tax parameters for capital companies and cooperatives and illustrates how they translate into effective combined tax burdens in Solothurn.
Statutory Cantonal & Capital Rates (Capital Companies & Cooperatives)
The table below outlines the main corporate tax parameters in Solothurn around the implementation of STAF, focusing on ordinary capital companies and cooperatives. For ease of reference, combined rates are illustrated using the city of Solothurn.
| From / to | Combined profit tax (canton + communes + federal) | Capital tax on equity (city of Solothurn) | Minimum capital tax | Comment |
|---|---|---|---|---|
| Until 31 Dec 2019 | Higher combined corporate income tax burden in the mid- to high-teens for ordinary companies in the city of Solothurn, prior to STAF-related rate reductions. | Capital tax on equity with progressive bands and municipal multipliers; combined effective capital tax rate somewhat above 0.17% for typical equity levels in the city of Solothurn. | Minimum capital tax rules already in place, ensuring a base amount is due even where profit and equity are low. Specific thresholds and amounts have evolved over time. | Pre-STAF regime with higher effective profit tax. Preferential regimes for certain status companies were available under the old law and have since been replaced by STAF-compliant instruments. |
| From 1 Jan 2022 | Combined effective corporate income tax burden (canton + communes + federal) for ordinary companies in the city of Solothurn of approximately 15.3% of profit before tax. Other municipalities show slightly lower or higher combined rates (e.g. about 13.9% in low-tax Kammersrohr). | Combined effective capital tax rate in the city of Solothurn of around 0.17% of taxable equity. In lower-tax municipalities such as Kammersrohr, the capital tax rate is closer to 0.14%. | Minimum capital tax of roughly CHF 434 per year in the city of Solothurn and approximately CHF 350 in lower-tax municipalities. Exact amounts depend on legal form and municipal multipliers. | STAF implementation: stepwise reduction of the effective profit tax rate to about 15.3% from 2022 onwards, introduction of an R&D super-deduction and patent box, and crediting of profit tax against capital tax so that capital tax functions as a minimum burden in low-profit years. |
The combined profit tax and capital tax rates quoted above are indicative values for ordinary companies in selected municipalities. They may change over time and can vary by municipality. For a concrete case, always consult the current Solothurn tax tariffs and use the official calculators of the Solothurn tax administration.
Effective Combined Tax Burden
Cantonal/communal + federal profit tax
The effective corporate income tax burden in Solothurn is the result of combining:
- Cantonal and communal profit tax on net profit before tax, determined by Solothurn’s corporate tax schedule and the tax factors of the municipality; and
- Swiss direct federal corporate income tax at 8.5% of profit after tax, which corresponds to roughly 7.8% of profit before tax because the tax is deductible.
After the STAF implementation and the stepwise rate reductions, external analyses indicate that the combined corporate income tax burden for a standard capital company in the city of Solothurn is around:
- 2020: approx. 16.2% of profit before tax;
- 2021: approx. 15.8% of profit before tax; and
- From 2022: approx. 15.3% of profit before tax.
Other municipalities may apply somewhat lower or higher combined rates. For example, one of the lowest-tax municipalities in the canton shows a combined profit tax burden of roughly 13.9% of profit before tax.
Compared with other cantons, Solothurn sits in the mid-range of Swiss corporate tax locations for ordinary companies: higher than low-tax cantons such as Zug or Nidwalden, but lower than some large cantons with combined rates above 18–20%.
Illustrative example (city of Solothurn)
Assume a standard capital company in the city of Solothurn with:
- Taxable profit before tax: CHF 1,000,000;
- Taxable equity: CHF 3,000,000;
- No use of patent box or R&D super-deduction in the base case; and
- No special tax holidays or unusual structures.
Then, very roughly:
- Combined cantonal/communal and federal profit tax will be on the order of CHF 153,000 (around 15.3% of profit before tax) in a recent-year scenario for the city of Solothurn.
- Capital tax at approximately 0.17% of CHF 3,000,000 corresponds to about CHF 5,100 of capital tax before applying crediting rules.
- Since profit tax (CHF 153,000) clearly exceeds capital tax (CHF 5,100), the profit tax is credited against capital tax, and no additional net capital tax is due; the capital tax acts as a minimum only in low-profit years.
- If the company begins to use the R&D super-deduction or the patent box on qualifying income, the cantonal/communal portion of the profit tax could be reduced, subject to the overall relief cap, and the combined rate on qualifying income could fall below the headline 15.3%.
For precise results, use the Solothurn tax tariffs and calculators for juristic persons for the relevant tax year and municipality.
The figures above are indicative and based on current public information. They cannot replace an official tax assessment or ruling. For significant investments, relocations or restructurings, always work with up-to-date official data and consider obtaining advance rulings from the Solothurn tax administration.
Capital Tax, Minimum Tax & STAF Instruments
Capital tax & minimum capital tax
Solothurn levies a capital tax on taxable equity for juristic persons, with cantonal rules and municipal multipliers:
- For ordinary capital companies and cooperatives in the city of Solothurn, the combined capital tax burden is around 0.17% of taxable equity.
- In low-tax municipalities such as Kammersrohr, the combined capital tax rate can be as low as roughly 0.14% of taxable equity.
- Certain entities with ideal purposes (ideelle Zwecke) benefit from exemptions up to specified thresholds (e.g. profit and capital below certain amounts) if their assets and income are exclusively and irrevocably dedicated to these purposes.
A key feature is that profit tax is credited against capital tax:
- If profit tax exceeds capital tax, net capital tax is effectively zero – the capital tax is fully offset.
- If profit tax is lower than capital tax, the capital tax is reduced by the profit tax amount and functions as a minimum tax.
- If no profit tax is due (loss year), capital tax alone is payable, subject to any exemptions.
In addition, there is a minimum capital tax. In the city of Solothurn, the minimum capital tax is around CHF 434 per year, while in certain low-tax municipalities it is closer to CHF 350. The exact thresholds and amounts vary by municipality and legal form.
STAF instruments: R&D super-deduction & patent box
Solothurn has implemented several STAF-compliant instruments to maintain competitiveness and support innovation:
- A 50% R&D super-deduction on qualifying research and development expenses (input promotion), typically based on qualifying personnel costs plus a lump-sum markup for infrastructure.
- A patent box for income from qualifying patents and comparable rights (output promotion), granting a reduction of the cantonal tax base for such income.
- An overall relief cap ensures that the combined effect of R&D deduction, patent box and certain step-up rules does not reduce the cantonal taxable profit below a prescribed proportion of accounting profit.
For companies with significant R&D and IP activities in Solothurn, these instruments can materially reduce the effective cantonal profit tax burden, while the participation relief mechanism mitigates tax on qualifying dividends and capital gains from participations.
In practice, the use of the R&D deduction and patent box should be backed by robust documentation (project descriptions, cost allocations, nexus documentation), and material cases are often clarified via advance tax rulings.
Modelling Tools & Calculators
To quantify the tax burden for a specific company in Solothurn, combine official tools with internal models and independent benchmarks:
| Tool | What it does | How to use it for Solothurn |
|---|---|---|
| Solothurn corporate tax tariffs & official guidance | Provide the statutory profit and capital tax schedules for juristic persons, municipal tax factors and commentary on the crediting mechanism between profit and capital tax, as well as exemptions for entities with ideal purposes. | Consult the sections on Gewinn- und Kapitalsteuer juristische Personen in the Solothurn tax handbook and the annually published tax tariffs. Use them to derive cantonal/communal components, minimum capital taxes and to verify how profit tax is credited against capital tax in specific scenarios. |
| Solothurn tax calculator & federal tools | Allow the calculation of tax burdens for individuals and, via federal tools, facilitate cross-cantonal comparisons for juristic persons. | Use the Solothurn tax calculator as far as available for juristic persons, together with the federal profit tax calculator, to approximate combined burdens and to validate internal models. When necessary, supplement with published examples and canton-specific guidance for companies. |
| Comparative corporate tax overviews | Independent reports and advisory firm overviews list combined effective corporate income tax rates and capital tax rates for cantonal capitals, including the city of Solothurn (approx. 15.3% profit tax and 0.17% capital tax). | Use these overviews to benchmark Solothurn against low-tax and high-tax cantons when making location choices or preparing presentations for boards and group tax committees. |
| TaxRep Solothurn calculator (this hub) | Applies Solothurn’s combined profit and capital tax parameters – including minimum capital tax, crediting of profit tax, R&D super-deduction and patent box – together with federal profit tax, to company-specific profit and equity figures. | See the calculator page of this hub once the Solothurn parameters are configured. Use it for multi-year scenario planning, “what-if” cases (different municipalities, equity levels, R&D and patent box usage) and Pillar 2 impact analysis. |
Planning Considerations
| Theme | Rate impact | What to watch |
|---|---|---|
| Choice of municipality within Solothurn | Combined corporate income tax and capital tax rates vary between the city of Solothurn and low-tax municipalities such as Kammersrohr (e.g. approx. 15.3% vs. 13.9% profit tax and 0.17% vs. 0.14% capital tax). | Compare municipalities using official tariffs and independent overviews. For material location choices, consider non-tax factors such as labour market, infrastructure and group substance requirements alongside the tax rate differentials. |
| Capital intensity & minimum capital tax | Capital tax and the minimum capital tax become particularly relevant for capital-intensive or low-margin businesses, especially in loss years when profit tax is low or zero. | Model multi-year scenarios including loss and low-profit years. Take into account that profit tax is credited against capital tax and that the minimum capital tax (e.g. around CHF 434 in the city of Solothurn) remains payable regardless of profit level. |
| Use of R&D super-deduction & patent box | The 50% R&D super-deduction and the patent box can substantially reduce the cantonal portion of Solothurn profit tax on qualifying activities, subject to the relief cap. | Identify qualifying R&D projects and IP assets, and ensure that documentation meets the canton’s expectations. For significant cases, obtain advance rulings on qualification, allocation of income and the application of the relief cap. |
| Participation relief & holding structures | Participation relief reduces profit tax on qualifying dividends and capital gains from participations; combined with the capital tax crediting mechanism, this can lead to relatively low effective tax burdens for holding and mixed structures. | Ensure that participations meet the statutory thresholds and that group structures are designed to make effective use of participation relief, while respecting substance requirements and foreign CFC or anti-hybrid rules. |
| Pillar 2 and global minimum tax | With a combined rate around 15.3% in the city of Solothurn, the canton sits slightly above the OECD global minimum tax benchmark of 15%, but the use of STAF instruments can reduce effective rates on certain income streams below that threshold. | For groups in scope of Pillar 2, model Solothurn entities within the group-wide effective tax rate and top-up tax calculation, especially when using R&D deductions, patent box or step-up mechanisms. |
FAQs
What is the corporate income tax rate in Solothurn?
For ordinary capital companies and cooperatives in the city of Solothurn, the combined corporate income tax burden – including cantonal, communal and federal tax – is around 15.3% of profit before tax from 2022 onwards. Other municipalities may apply slightly lower or higher combined rates, with some low-tax municipalities showing combined profit tax burdens of around 13.9%.
What is the capital tax rate for companies in Solothurn?
The combined capital tax burden for ordinary companies in the city of Solothurn is around 0.17% of taxable equity. In low-tax municipalities such as Kammersrohr, the combined capital tax rate is closer to 0.14%. Profit tax is credited against capital tax, so in profitable years capital tax is often fully offset.
How does the crediting of profit tax against capital tax work?
Solothurn credits profit tax against capital tax. If profit tax exceeds capital tax, no net capital tax is payable. If profit tax is lower than capital tax, the capital tax is reduced by the profit tax amount, so that at least the capital tax (or the minimum capital tax) is paid. In loss years, capital tax alone is due, subject to exemptions for small or ideal-purpose entities.
Is there a minimum capital tax in Solothurn?
Yes. Solothurn applies a minimum capital tax. In the city of Solothurn, the minimum capital tax for companies is around CHF 434 per year, while certain low-tax municipalities apply minimum capital taxes of around CHF 350. The exact amounts depend on legal form and municipal multipliers and can change over time.
Does Solothurn offer an R&D super-deduction and a patent box?
Yes. As part of its STAF implementation, Solothurn offers a 50% R&D super-deduction on qualifying research and development expenses and a patent box for income from qualifying patents and comparable rights. Both instruments are subject to an overall relief cap and require proper documentation and, in material cases, often advance tax rulings.
Where can I check the current Solothurn corporate tax rates and use official tools?
The most reliable sources are the Solothurn tax administration’s official publications, including the sections on Gewinn- und Kapitalsteuer für juristische Personen in the Solothurn tax handbook and the annually updated tax tariffs. For comparisons and modelling, you can also use federal tools and independent corporate tax overviews. For important structuring or investment decisions, it is advisable to confirm the applicable rates and interpretations in writing or via advance tax rulings.
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