A balance guaranteed swap in which one leg pays LIBOR plus a spread, while the other leg pays the average official base rate during a respective period. The LIBOR leg pays the coupon fixed at the beginning of the period, but the base rate leg pays a fixed amount at the end of the period. This agreement allows the notional principal amount to be any value within a pre-determined range. The LIBOR base rate payer has the right to determine the size of the notional principal at the beginning of each resetting period.