Körperschaftsteuererklärung (Corporate Tax Return)
The annual corporate income tax return (KSt) for Austrian GmbHs and AGs. Covers all taxable profits for the financial year and reconciles advance payments made during the year.
Who this applies to
- Austrian GmbH
- Austrian AG
- Other Austrian corporate entities (Genossenschaften, Vereine with commercial activity)
- Foreign companies with Austrian branch offices
What to file
Körperschaftsteuererklärung (Form K1 and supplements). Includes profit/loss statement, balance sheet adjustments, loss carry-forward claims, and supporting schedules for related-party transactions.
How to file
Electronically via FinanzOnline (www.finanzonline.gv.at) — paper filing still available but strongly discouraged and subject to the earlier 30 April deadline. Steuerberater submit on behalf of clients via FinanzOnline professional portals.
Payment due
Quarterly advance payments (Vorauszahlungen) are due 15 February, 15 May, 15 August, and 15 November throughout the year. Any final balance (Nachzahlung) or refund is settled after the Finanzamt issues the Körperschaftsteuerbescheid (tax assessment notice), typically 2–6 months after the return is filed.
Penalties for missing this deadline
Late filing penalty (Verspätungszuschlag) of up to 10% of the assessed tax liability. Non-filing triggers compulsory assessment (Schätzung) by the Finanzamt, which invariably results in a higher assessed liability than the actual profit. Persistent non-filing can result in enforcement proceedings.
Filing checklist
- Prepare final UGB (commercial) accounts (Jahresabschluss) — the tax calculation starts here
- Make all tax adjustments to convert commercial profit to Steuerbilanz profit
- Calculate any Verlustabzug (prior year losses, max 75% of current year profit)
- Verify quarterly advance payments made during the year and reconcile against final liability
- Check related-party transactions for transfer pricing compliance
- File electronically via FinanzOnline or through registered Steuerberater
- File Mindestkörperschaftsteuer credit claim if applicable
Documents you'll need
- Jahresabschluss (UGB annual accounts — balance sheet and P&L)
- Trial balance or detailed ledger extract
- Fixed asset register with AfA calculations
- Shareholder loan documentation for thin cap analysis
- Prior year KSt assessment (Bescheid) for carried loss verification
Common mistakes to avoid
- Filing on paper unnecessarily — electronic deadline is 2 months later
- Not applying the 75% Verlustabzug cap correctly, resulting in underpayment
- Missing the Mindestkörperschaftsteuer credit claim for prior years' €500 minimum payments
- Omitting related-party disclosure supplements required for shareholding above 25%
Never miss a Austria deadline
AccountsOS tracks every Finanzamt Österreich / BMF and Firmenbuch (Commercial Register) — USP deadline and reminds you weeks ahead.
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