Switching to Estonian CIT in Poland during the tax year

Reviewed: 13 October 2026 · Polish law and taxation

A Polish company can elect the regime commonly called Estonian CIT during its existing tax year. The practical challenge is creating a reliable boundary between the ordinary corporate income tax system and the lump-sum regime. Management needs a coordinated accounting and tax timetable before filing the election. For foreign owners, the first question is whether the ownership structure permits access at all.

Check eligibility before selecting a date

The conditions in Article 28j of the Polish CIT Act must be considered together with the exclusions in Article 28k. Eligible legal forms include a Polish limited liability company, but all shareholders must be individuals. A Polish subsidiary owned by a foreign corporate parent therefore cannot assume that it qualifies. The company must also satisfy restrictions on its own equity interests and the applicable financial-reporting requirements.

Revenue composition and employment need separate testing. Less than 50% of the previous year's revenue, including VAT, may come from the statutory categories. These include specified financial receipts and certain related-party transactions generating no economic added value or only negligible added value. Ordinary group sales are not automatically disqualifying. Employment rules contain detailed alternatives and concessions for qualifying small taxpayers and newly established businesses.

Treat the accounting cut-off as a project

Article 28j(5) requires a company switching mid-year to close its accounting books on the last day of the month preceding its first month under the regime and prepare financial statements under Polish accounting rules. Books reopen on the first day of the new regime. The election notification is due by the end of the first month of the first tax year under Estonian CIT.

The finance team should identify who supplies the final entries, prepares the statements, obtains the required signatures and handles the shortened ordinary-CIT period. A group reporting package is not automatically a substitute for the company's statutory financial statements. Filing ZAW-RD does not remove the accounting obligations. These tasks should be scheduled before management commits to the intended switch date.

Reconcile the opening adjustment

Article 7aa requires information reconciling specified differences between tax treatment and accounting profit. This opening adjustment is not a blanket tax on every balance-sheet difference. Earlier profits and uncovered losses must also be identified separately within equity, so future distributions can be traced to the correct period.

Where tax arises from the opening adjustment, its payment treatment depends on how long the company remains continuously within the regime. The liability expires after at least four consecutive tax years of application. A conversion-related income charge is a separate issue with separate rules. Management should not apply the opening-adjustment treatment to a conversion without checking the statutory conditions and the restructuring history.

Illustrative example: a July election

A Polish company owned directly by two individuals plans to switch on 1 July. Its accountant prepares a 30 June closing process and the required financial statements. The July notification deadline is entered into the compliance calendar. During reconciliation, an unresolved depreciation difference and unallocated historical profits emerge. The team resolves both before finalising the transition records rather than carrying unsupported balances into the new regime.

Four tax years: map the actual calendar

Expiry of the preliminary-adjustment tax liability depends on at least four consecutive tax years of uninterrupted lump-sum taxation, rather than an assumed 48 months. A mid-year entry can produce a shorter first period. Map the start and end of each tax year under the applicable rules and the company’s financial year; the phrase “four years in the system” is not a payment timetable. The basis is Article 7aa(5)(1) of the Polish CIT Act.

Documents and next steps

1. Confirm shareholder eligibility and the company's restructuring history.
2. Test revenue, employment and financial-reporting conditions.
3. Assign the closing accounts, statements and signature tasks.
4. Reconcile tax-accounting differences and historical equity balances.
5. Review shareholder transactions and establish ongoing monitoring.

Send TLP the latest financial statements, trial balance, ownership chart and proposed switch date. These documents allow a focused readiness review and a practical list of actions before the election is filed. Any home-country consequences for foreign shareholders require a separate assessment alongside the Polish analysis.