Since bank records have to be kept in YTL, for foreign currency indexed personal loans, where customers repay in foreign currency, at every installment period, the difference (in foreign currency exchange rates) between customer payments and bank accounting records is subjected to KKDF BSMV (Resource Utilization Support Fund and Banking and Insurance Transaction Tax) taxes at pre-set rates according to Central Bank instructions and are transferred to the respective institutions. The KKDF is collected in terms of the difference between the remaining total principal and the exchange rate and the BSMV in terms of the difference between the principal and the exchange rate within the installment.