How is the interest calculated and charged?  

Interest is calculated daily on the entire outstanding and utilized capital, taking as basis a year with 360 days and the actual number of days in each month.  The amounts owed will also be subject to taxes demandable under the law and regulations in force at each moment. Currently, stamp duty is added to the interest provided in funding 17.3.1. of TGIS, right now at 4%.   Interest will be paid monthly in arrears, due on the first day of each month of the calendar year.