Herein described is a computer based system, a computer-readable storage media, and a method for optimizing the amount of currency transferred to a custodial inventory vault of a depository institution. The currency comprises ten and twenty dollar bills. For example, the method comprises determining a first amount of ten and twenty dollar bills, subtracting a second amount corresponding to a minimum vault holding requirement from the first amount to yield a third amount. The third amount is transferred along with a predetermined fourth amount to the custodial inventory vault of the depository institution. The predetermined fourth amount may be chosen to minimize or obviate an occurrence of an ending cash balance of ten and twenty dollar bills being less than the second amount. The third and fourth amounts of ten and twenty dollars bills are held in the custodial inventory vault and provide a monetary benefit for the depository institution.