Abstract
The aim of this paper is to deepen the study of relationships between the use of compound capitalization/discount formulas and the prohibition of compounding interests in the Italian legislation. To this purpose, we study analytically the consequences of using simple capitalization in the determination of the installment, proving how this approach leads to ambiguous situations, in addition to a greater burden on the debtor with respect to normal depreciation French. The ambiguity, in particular, lies in the non uniqueness of the way of calculating the installment and the related impossibility to choose among different installment plans only according to the APR.