Calculation, Payment and Adjustment of Monthly Corporate Income Tax Advances in 2026

Calculation and Payment of Monthly Tax Advances

Corporate income taxpayers are required to pay their corporate income tax through monthly advance payments in accordance with the Corporate Income Tax Law. This requirement does not apply to non-profit organizations or taxpayers undergoing bankruptcy or liquidation proceedings.

The amount of the monthly advance payment is determined by the taxpayer under the self-assessment principle, based on the taxable profit reported in the tax return for the previous tax period. Capital gains and capital losses are excluded from this calculation. No decision from the Tax Administration is required, and monthly advances must be paid by the 15th day of the month for the preceding month.

The newly calculated advance payment becomes applicable starting from the month following the submission of the tax return. Until then, the taxpayer continues to pay advances in the amount applicable for December of the previous tax year.

For example, if the tax return is submitted in June, the new monthly advance first applies to June, with payment due by 15 July.

In practice, companies expecting a lower tax liability often submit their tax returns as early as possible in order to benefit sooner from reduced monthly advances. Conversely, companies anticipating a higher tax liability may wait until the statutory filing deadline, allowing them to continue paying lower advances for a longer period.

Following the submission of the tax return, two scenarios are possible:

• if the newly calculated advance exceeds the amount previously paid, the taxpayer must pay the difference together with the advance payment for the month in which the return was filed;
• if the new advance is lower, the resulting overpayment may be credited against future monthly advance payments.

Adjustment of Monthly Advance Payments

If significant changes in business performance occur during the year, a taxpayer may adjust its monthly advance payments by filing an electronic tax return together with an updated tax balance.

No separate application or approval from the Tax Administration is required. The revised advance payment becomes effective from the first day of the month following the month in which the tax return was submitted.

The adjustment may result in an increase or decrease of the monthly advance, the termination of the obligation to pay advances, or the commencement of such an obligation during the year, depending on the taxpayer’s current business results.

It is important to note that adjusting the advance payment does not require a recalculation of the amounts already paid for previous months. The revised amount applies only to future advance payments.

However, if the Tax Administration determines during a tax audit that the submitted tax return contains inaccurate or incomplete information affecting the amount of the advance payment, it may assess the tax liability by issuing a formal tax assessment decision.