Reviewed by the editorial team of Symbol Consulting DMCC
The European Central Bank raised its main refinancing operations rate to 2,65 % from 16 September 2026 (primary source Národná banka Slovenska, ECB rate table, 10. 9. 2026). Four times that rate is 10,6 %, and yet late payment interest on arrears arising in October 2026 is charged at 15 % a year, because of the floor in § 156(2) of the Slovak Tax Code. For the finance department of a Slovak s.r.o. with a foreign owner, what matters is that the day the arrears arise fixes the rate.
Late payment interest on arrears of 20 000 euros: a worked case
Model situation: arrears of 20 000 euros paid 45 days late. For arrears arising after 16 September 2026 interest comes to 369,86 euros: 20 000 × 15 % × 45 ÷ 365. The same arrears arising in April 2024 would carry 443,84 euros at the then rate of 18 % (4 × 4,50 %). Both are Symbol Consulting calculations on the formula of the Financial Directorate (primary source Finančné riaditeľstvo SR, support page „Úrok z omeškania“).
The difference of 73,98 euros (both amounts with a divisor of 365; with 366 for the leap year 2024 the result is 442,62 euros and the difference 72,76 euros) lies neither in the amount owed nor in the number of days, but in the ECB rate valid on the day the arrears arose.
The § 156(2) formula: numerator, denominator and rate
Late payment interest under § 156(2) of Act No. 563/2009 Coll. on Tax Administration is the product of the amount owed, the annual rate and the number of days of delay, divided by the number of days in the year. The annual rate is four times the base interest rate of the European Central Bank, but at least 15 % (primary source Slov-lex, Tax Code as in force from 1. 9. 2026).
The numerator holds the amount owed under § 156(1) — tax or a tax difference, an advance payment, an instalment or tax withheld at source — and the number of days of delay. Days run from the day after the due date up to and including the day of payment, for at most four years. For an advance payment, § 156(4) caps the count at the deadline for filing the tax return.
The Tax Code does not define the term „base interest rate of the ECB“. § 17(1) of Act No. 659/2007 Coll. on the Introduction of the Euro does: it is the rate the European Central Bank sets for the Eurosystem’s main refinancing operations (primary source Slov-lex, Act No. 659/2007 Coll., § 17(1)). It is therefore not the deposit facility rate, which stands at 2,50 % from 16 September 2026.
The Act does not state the denominator explicitly. The Financial Directorate gives 365 or 366, but its examples divide by 366 even for days in 2023, which was not a leap year: for 4 000 euros and 31 days the result is 50,8196 euros instead of 50,9589 euros. Under § 156(6)(b) the tax office does not assess interest of up to 5 euros.
The rate is fixed on the day the arrears arise, not the day of payment
The base interest rate of the European Central Bank enters late payment interest on a single day: the day the tax arrears arise, or for an advance payment and an instalment the day after they fall due. Under § 156(2) of the Tax Code it then stays unchanged for the whole period of delay, so neither a rise nor a cut in the rate during the delay affects interest on arrears that already exist.
At a rate of 2,65 % the 15 % floor applies, because four times the rate gives 10,6 %. Four times the rate exceeds 15 % only when the main refinancing operations rate is above 3,75 %. According to the Národná banka Slovenska table updated on 10 September 2026, that was last the case from 21 June 2023 to 17 September 2024: rates of 4,00 %, 4,25 % and 4,50 % gave 16 %, 17 % and 18 % a year.
Arrears from that period that remain unpaid therefore still accrue 16 to 18 % a year. Arrears arising from 20 September 2023 to 11 June 2024, those at 18 %, will reach the four-year cap on delay in 2027 and 2028.
Penalties under § 155(1)(f) to (h): the same ECB rate, different multiples
Three penalties under § 155(1)(f) to (h) of the Tax Code use the same base interest rate of the European Central Bank as late payment interest, but with a different multiple, a different floor and a different decisive day. At a rate of 2,65 %, the floors of 3 %, 7 % and 10 % a year apply in all three cases (primary source Finančné riaditeľstvo SR, support page „Pokuty – sadzby pokút“).
| Provision | Situation | Multiple of ECB rate | Annual floor | Multiple exceeds floor at ECB rate above | Rate at 2,65 % | ECB rate taken on the day of |
|---|---|---|---|---|---|---|
| § 156(2) | late payment interest | 4× | 15 % | 3,75 % | 15 % | arrears arising |
| § 155(1)(g) | supplementary return before an audit starts | 1× | 3 % | 3,00 % | 3 % | filing the supplementary return |
| § 155(1)(h) | supplementary return within 15 days after an audit starts | 2× | 7 % | 3,50 % | 7 % | filing the supplementary return |
| § 155(1)(f) | tax increased by the administrator’s decision | 3× | 10 % | 3,33 % | 10 % | delivery of the decision |
The numerator of the penalty under points (g) and (h) is the difference between the amount in the supplementary return and in the previous return; under point (f) it is the amount by which the administrator increased the tax. Under § 155(2) the penalty is at least 1 % and at most 100 % of the assessed amount; the office does not impose a penalty of up to 5 euros. Relief from sanctions under § 157 is not part of the calculation.
By the Symbol Consulting calculation the penalty reaches the 1 % limit at a rate of 3 % only after 121,7 days (365 × 1 ÷ 3), at 7 % after 52,1 days and at 10 % after 36,5 days. For a model difference of 20 000 euros, a supplementary return filed 200 days after the deadline leads to a penalty of 328,77 euros; filed after 60 days, to a penalty of 200 euros, because 20 000 × 3 % × 60 ÷ 365 gives only 98,63 euros.
The deadline from which the penalty runs is, for corporate income tax, three months after the end of the tax period, and it can be extended by notification by three months, or by six months where there is foreign income (consulting source PwC Worldwide Tax Summaries, reviewed 9. 9. 2026). If the taxpayer pays the amount imposed within 15 days of delivery of the assessment decision, the tax office imposes the penalty under point (f) at two thirds (§ 155(17)).
Recalculating the tax administrator’s decision from five data points
A tax administrator’s decision on late payment interest or on a penalty under § 155(1)(f) to (h) can be recalculated from five data points, each of which matches one variable of the formula. In the version of the Tax Code in force from 1 January 2027, § 155 and § 156 are unchanged (primary source Slov-lex, version in force from 1. 1. 2027).
- Amount owed: the arrears under § 156(1), for a penalty the tax difference or the amount increased by the decision, not the whole tax for the period.
- Decisive day: for interest the day the arrears arose, for a penalty under points (g) and (h) the day the supplementary return was filed, for point (f) the day the decision was delivered.
- Rate: the multiple of the main refinancing operations rate valid on the decisive day, or the floor if higher.
- Number of days: from the day after the due date or after the filing deadline; for interest at most four years.
- Limits: the office imposes neither interest nor a penalty of up to 5 euros; a penalty is at least 1 % and at most the assessed amount.
The rate of a penalty on a supplementary return is fixed on the day it is filed. The ECB Governing Council decides on rates at its meetings on 28–29 October and 16–17 December 2026 (primary source European Central Bank, 2026 meeting calendar), but the day a change takes effect decides: the increase of 10 September 2026 applies from 16 September 2026. The penalty under point (g) changes only at a rate above 3,00 %, under point (h) above 3,50 %, under point (f) above 3,33 % and late payment interest above 3,75 %; a step of 0,25 percentage points to 2,90 % would cross no threshold.
Zdroje a dáta
Primary sources: Slov-lex — Act No. 563/2009 Coll., versions from 1. 9. 2026 and from 1. 1. 2027, and Act No. 659/2007 Coll., § 17(1); Finančné riaditeľstvo SR — support pages „Úrok z omeškania“ and „Pokuty – sadzby pokút“; Národná banka Slovenska — ECB rate table of 10. 9. 2026, checked against the ECB press release; European Central Bank — meeting calendar.
Consulting source: PwC Worldwide Tax Summaries, reviewed 9 September 2026, for the filing deadline. Symbol Consulting calculation: the worked amounts in euros, the ECB rate thresholds in the table and the numbers of days at which the penalty reaches 1 %.
This material was reviewed by the editorial team of Symbol Consulting DMCC, an advisory firm that provides company setup and licensing, tax and regulatory compliance, and market entry consulting across multiple countries.
This text is a general analysis of the regulations in force and does not constitute legal, tax, immigration or financial advice.