Thurgau Corporate & Capital Tax - Forms & Deadlines
Last updated: 14 Dec 2025
Thurgau Corporate & Capital Tax — Forms & Deadlines
What companies need to file for the Canton of Thurgau’s corporate profit tax and capital tax: who is required to file, how to use eFisc, how online extensions work (eFristverlängerung), key documents, filing timing, assessments, payments, interest, and tax clearance in practice.
Who Must File
- Resident companies with statutory seat or effective place of management in the Canton of Thurgau must file a combined corporate income and capital tax return (Steuererklärung für juristische Personen) for each tax year.
- Nonresident entities with a taxable nexus in Thurgau (e.g., a permanent establishment or Thurgau-situs real estate) generally file a limited Thurgau return covering their local taxable base.
- All legal forms treated as “juristic persons” (e.g. AG, GmbH, cooperative, certain foundations and associations) file, even in loss years or where only minimum capital tax is due.
- Groups with multiple Swiss entities file separate returns for each legal entity registered in Thurgau; group information is provided via attachments (e.g., TP and intercompany documentation) rather than a consolidated return.
Key Forms & Documents (Thurgau Corporate & Capital Tax)
| Item | Purpose | Typical contents |
|---|---|---|
| Corporate tax return (juristic persons) | Main filing for Thurgau corporate profit tax and capital tax, prepared using the official cantonal workflow (commonly with eFisc). | Identifying data; tax period; reconciliation from accounting profit to taxable profit; loss carryforwards; capital tax base; participation relief information; allocations (if applicable). |
| Financial statements | Basis for assessment; must reconcile to the tax return. | Signed annual report, balance sheet, income statement, notes, appropriation of profits, audit report (if applicable), prior-year comparatives. |
| Tax reconciliation & schedules | Explains adjustments between statutory accounts and taxable result and documents capital tax base. | Add-backs/deductions; depreciation schedules; provisions; hidden equity analysis; participation deduction calculation; allocation of equity to Thurgau nexus. |
| Group & related-party documentation | Supports transfer pricing, interest conditions and intra-group services. | Group structure chart; intercompany agreements; TP documentation; overview of loans/guarantees; rulings (if any). |
| Extension request (eFristverlängerung) | Requests additional time to file beyond the ordinary deadline using Thurgau’s online extension service. | Tax period; company identifiers; requested new filing date; confirmation/receipt of the extension request. |
| Payments & account extracts | Evidence of advance payments and final settlement to match assessments. | Advance tax invoices; payment confirmations; reconciliation of assessed tax with instalments; interest/refund statements. |
Thurgau provides electronic tooling around corporate filings (including online extension requests). If you run into software issues with eFisc, the canton’s published support contact includes fisc.sv@tg.ch.
Deadlines & Extensions
Standard timing
In Thurgau, the controlling due date is the deadline stated in the filing communication for the relevant tax period. For many calendar-year companies, the ordinary corporate filing deadline is commonly set around mid-year (often end of June), but you should follow the date shown in the tax office’s filing notice for your entity.
If you have a Thurgau tax nexus but have not received filing details, contact the cantonal tax administration to clarify registration and deadlines.
Extensions (online: eFristverlängerung)
Thurgau offers an online process for filing extensions for juristic persons. For the 2024 tax return, the cantonal guidance states that an extension until 31 December 2025 is free of charge when requested online.
Extension requests should be lodged before the original deadline. An extension to file does not automatically extend the time to pay; interest may accrue on unpaid balances even if the filing deadline is extended.
Assessment, Payment & Interest
- Assessment. After the return is processed, the Thurgau tax administration issues an assessment decision covering cantonal/communal and direct federal tax components for the company, including capital tax.
- Advance payments. Thurgau typically issues advance invoices based on prior periods or estimates; these instalments are credited against the final assessment.
- Payment mechanics. Taxes are paid via the channels shown on invoices/assessments (e-banking, payment slip/QR-bill, etc.). Always use the correct reference number to allocate payment to the right tax period.
- Interest & penalties. Interest is normally charged on late payments; penalties may apply for late filing, incomplete disclosure or tax evasion. If liquidity is tight, request an instalment plan proactively.
- Objections/appeals. The assessment letter specifies the objection (Einsprache) deadline and procedure; objections should be filed in writing within the stated period and supported by evidence.
Tax Clearance & Commercial Register (Corporate Changes)
- Events such as dissolution, liquidation, mergers, de-mergers or migrations of seat often require tax clearance/coordination before the commercial register completes registration steps.
- For liquidations, the tax office typically assesses taxes up to the liquidation date and may require interim/final returns; distributions can trigger additional income or withholding tax consequences.
- For seat relocation to/from Thurgau, coordinate tax opening/closing balance sheets and agree allocation of hidden reserves and equity between cantons.
- For restructurings under Swiss tax neutrality rules, advance rulings are frequently used to secure treatment at cantonal and federal level.
Submission Checklist
| Document | Included? | Notes |
|---|---|---|
| Completed corporate tax return (Thurgau, juristic persons) | ⬜ | Prepared using the cantonal process/software for the correct tax year. |
| Signed financial statements & audit report (if applicable) | ⬜ | Balance sheet, income statement, notes, appropriation of profits. |
| Tax reconciliation profit → taxable profit | ⬜ | Adjustments for non-deductible expenses, provisions, depreciation, etc. |
| Capital tax base reconciliation | ⬜ | Equity per accounts, hidden equity (if any), and allocation to Thurgau nexus. |
| Schedules for participation relief / exemptions | ⬜ | Dividend and capital gains details; holding percentage; acquisition cost. |
| Group and related-party overview | ⬜ | Structure chart, intercompany contracts, TP documentation. |
| Supporting documentation for major items | ⬜ | Loan agreements, valuations, impairment tests, restructuring documents. |
| Confirmation of advance tax payments | ⬜ | To reconcile assessments and check interest/penalties. |
| Extension request (if filing after ordinary deadline) | ⬜ | Requested online via eFristverlängerung before the deadline expires. |
| Signature by authorised signatories (if required by the submission method) | ⬜ | Follow the Thurgau filing instructions for signatures/authorisations for your workflow. |
Where to Submit / Contact
Steuerverwaltung Thurgau handles corporate income and capital tax matters for legal entities. Contact details published for the cantonal tax administration include:
Steuerverwaltung Thurgau
Schlossmühlestrasse 15
8510 Frauenfeld, Switzerland
Tel: +41 58 345 30 30 · Email: info.sv@tg.ch
eFisc (software) support email: fisc.sv@tg.ch
Need help with your Thurgau corporate or capital tax filings? Our Swiss corporate tax work is handled by Sesch TaxRep GmbH, Buchs SG. For a fixed-fee engagement, please contact us with your company details, latest financial statements and tax period.
FAQs
What is the filing deadline for companies in Thurgau?
The controlling deadline is the date stated in the filing communication for your tax period. If you need more time, request an extension before the due date (Thurgau provides an online extension service for juristic persons).
How do extensions work for juristic persons in Thurgau?
Thurgau provides an online extension process (eFristverlängerung). The canton’s guidance indicates that, for the 2024 corporate return, an online extension up to 31 December 2025 is free of charge. Request the extension before the original deadline.
Can I extend time to pay as well as to file?
An extension to file does not automatically extend the time to pay. If you expect late payment or require instalments, contact the tax office proactively; interest may accrue on outstanding balances regardless of filing extensions.
Do small or loss-making companies still have to file?
Yes. Juristic persons with a Thurgau tax nexus normally must file a corporate tax return even in loss years or where only minimum capital tax is due. Filing documents the position and preserves loss carryforwards where applicable.
Who should sign the Thurgau corporate tax return?
The return should be signed by persons authorised to represent the company under the commercial register signing rules (individual or joint signature), where the submission method requires signatures. A fiduciary may assist, but typically does not replace the company’s own signature requirements.
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