Aargau Corporate & Capital Tax - Forms & Deadlines
Last updated: 14 Dec 2025
Aargau Corporate & Capital Tax — Forms & Deadlines
What companies need to file for the Canton of Aargau (AG) corporate profit tax and capital tax: who is required to file, how to use eTAX AARGAU (Juristische Personen), key documents, ordinary filing deadlines, extensions via eFristenJP, 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 Aargau must file a corporate income and capital tax return (Steuererklärung für juristische Personen) for each tax year.
- Nonresident entities with a taxable nexus in Aargau (e.g., a permanent establishment or Aargau-situs real estate) generally file a limited Aargau return covering their local taxable base.
- All legal forms treated as “juristic persons” (e.g. AG, GmbH, cooperative, certain foundations and associations) generally file even in loss years or where only minimum capital tax is due.
- One return per legal entity. Groups file separately per entity registered in Aargau; group information is provided via attachments (transfer pricing, intercompany financing, rulings) rather than a consolidated return.
Key Forms & Documents (Aargau Corporate & Capital Tax)
| Item | Purpose | Typical contents |
|---|---|---|
| Corporate tax return (juristic persons) | Main filing for Aargau corporate profit tax and capital tax, typically prepared using eTAX AARGAU (JP) or the official PDF forms. | Identifying data; tax period; reconciliation from accounting profit to taxable profit; loss carryforwards; capital tax base; participation relief; SV17/STAF items (if applicable); allocation schedules (if relevant). |
| eTAX AARGAU (JP) | Official cantonal software for juristic persons; enables online transmission with the code from the filing letter. | Online transmission; ability to attach PDFs (e.g., financial statements); paper printing option if needed. |
| Financial statements | Basis for assessment; must reconcile to the return. | Signed annual report, detailed balance sheet and income statement, notes/annex, appropriation of profits, audit report (if applicable), prior-year comparatives. |
| Account detail (trial balance / Saldo list) | Required where the annual accounts use aggregated positions. | Saldo list showing all account balances (supporting the detailed balance sheet and P&L). |
| Tax reconciliation & schedules | Explains adjustments between statutory accounts and taxable result and documents capital tax base. | Add-backs and deductions; depreciation schedules; provisions; hidden equity schedule; participation deduction worksheet; equity allocation (if relevant). |
| 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 (eFristenJP) | Requests additional time to file beyond the ordinary deadline. | Register number (6/7 digits) or UID; selection of requested new due date; optional email confirmation. |
| Payments & account extracts | Evidence of advance payments and final settlement to match assessments. | Advance invoices/instalments; payment confirmations; reconciliation of assessed tax with instalments; interest/refund statements. |
Aargau provides downloadable eTAX software and PDF forms/“Wegleitungen” for juristic persons. Online transmission uses the personal code from the filing letter. Since tax year 2021, Aargau’s electronic submission no longer requires a signed “Freigabequittung” (older years may differ).
Deadlines & Extensions
Standard timing (ordinary deadline)
In Aargau, the filing deadline is linked to the approval of the annual accounts (30 days after approval by the general meeting), and the general meeting must usually be held within six months after year-end.
For all companies, the cantonal guidance states that the ordinary filing deadline expires on 31 October of the calendar year following the tax period (e.g., for the tax period 2024, ordinarily 31 Oct 2025), unless the tax office sets a different date in its filing request.
Extensions (eFristenJP)
Aargau offers an online extension tool for juristic persons: eFristenJP. Within the online tool, you can choose a requested extension date up to a maximum of 31 December. Longer extensions require a written request.
Extension requests should be filed before the existing deadline expires. An extension to file does not automatically extend the time to pay; interest may accrue on unpaid balances even where the filing deadline has been extended.
Assessment, Payment & Interest
- Assessment. After processing, the Aargau tax administration issues an assessment decision covering cantonal and communal components (and direct federal tax) including capital tax.
- Advance payments. Aargau typically issues provisional invoices/instalments based on prior periods or estimates; these are credited against the final assessment.
- Payment mechanics. Pay using the references indicated on invoices/assessments (e-banking, QR-bill, etc.) to allocate payments to the correct tax period.
- Interest & penalties. Interest is normally charged on late payments; penalties may apply for late filing or incomplete disclosure. Where liquidity is tight, instalment plans can be requested.
- Objections/appeals. The assessment letter specifies objection deadlines and procedure; objections should be filed in writing with supporting evidence.
Tax Clearance & Commercial Register (Corporate Changes)
- Corporate events such as dissolution, liquidation, mergers, de-mergers, or seat migrations often require tax coordination/clearance before commercial register steps are completed.
- For liquidations, the tax office typically assesses taxes up to the liquidation date and may request interim/final returns; distributions can trigger additional income or withholding tax consequences.
- In seat relocation cases (to/from Aargau), coordinate tax opening/closing balance sheets and allocate hidden reserves and equity between cantons.
- For restructurings under Swiss tax neutrality rules, advance tax rulings are frequently used to secure cantonal and federal treatment.
Submission Checklist
| Document | Included? | Notes |
|---|---|---|
| Completed corporate tax return (Aargau, juristic persons) | ⬜ | Prepared using eTAX AARGAU (JP) or the official PDF forms for the correct tax year. |
| Detailed financial statements & audit report (if applicable) | ⬜ | Detailed balance sheet, income statement, notes/annex, appropriation of profits. |
| Trial balance / account detail (if required) | ⬜ | Saldo list where the annual accounts contain aggregated positions. |
| 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 schedules (if applicable). |
| Schedules for participation relief / exemptions | ⬜ | Dividends/capital gains details; holding percentage; acquisition cost. |
| Group and related-party overview | ⬜ | Structure chart, intercompany contracts, TP documentation, loan/guarantee overview. |
| Supporting documentation for major items | ⬜ | Loan agreements, valuations, impairment tests, restructuring documents, rulings. |
| Confirmation of advance tax payments | ⬜ | To reconcile assessments and check interest/penalties. |
| Extension request (if filing after ordinary deadline) | ⬜ | Requested online via eFristenJP (up to 31 December) or in writing for longer requests. |
Where to Submit / Contact
Kantonales Steueramt Aargau — Sektion Juristische Personen handles corporate income and capital tax returns for juristic persons in Aargau. Submission details (online transmission code, address sheet, attachment requirements) are typically provided with the filing letter for the relevant period.
Kantonales Steueramt Aargau — Sektion Juristische Personen
Tellistrasse 67
Postfach, 5001 Aarau, Switzerland
Tel: +41 62 835 26 00 · Email: ksta.jp@ag.ch
Need help with your Aargau 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 Aargau?
Aargau’s guidance states that the filing deadline runs 30 days after approval of the annual accounts by the general meeting, and that the ordinary cantonal filing deadline is 31 October of the calendar year following the tax period (unless the tax office sets a different date in its filing request).
How do extensions work in Aargau for juristic persons?
You can request an extension online using eFristenJP (using your register number or UID). In the tool, an extension can be selected up to a maximum date of 31 December. Longer extensions must be requested in writing.
Can I file electronically in Aargau?
Yes. Aargau provides eTAX AARGAU for juristic persons and allows online transmission using the personal code from the filing letter. Attachments (such as financial statements) can be transmitted as PDFs and/or submitted as instructed for your filing.
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 loss-making companies still have to file?
Yes. Juristic persons with an Aargau tax nexus generally 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.
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