Nominal Annual Cost of Credit versus confusingly named and incorrectly calculated ”Rzeczywista Roczna Stopa Oprocentowania (RRSO)”

Abstract

The article examines the problem of the “rzeczywista roczna stopa oprocentowania – RRSO” (i.e., the annual percentage rate of change, APRC) indicator, the calculation and publication of which was imposed on credit institutions by EU directives and the Polish Act on Consumer Credit.
The purpose of the research is to prove that the name of this measure adopted in Polish is incorrect and to explain that it does not inform about the actual cost incurred by the borrower. This is due to the fact that the mathematical formula used to calculate it is not based on the nominal but on the effective interest rate, i.e., the rate taking into account the capitalization of interest, which is not applicable in loan agreements. In this way, the RRSO distorts (overestimates or underestimates) the actual cost of the loan and should be called the effective annual cost of loan (efektywny roczny koszt kredytu – ERKK) or the effective annual cost of debt (efektywny roczny koszt długu – ERKD), and the statutory definition should clearly indicate that the RRSO is the effective rate and does not reflect the true cost of the loan paid by the consumer. The article also shows that a better solution (though not ideal) for determining the true cost of loan would be to replace the current formula for calculating the APRC (resulting in the effective rate taking into account the compound interest) with the well-known formula for the nominal internal rate of return (IRR) – used for more than half a century in the US.