Systems, computer programs encoded on non-transitory memory, and computer-implemented methods to make available new credit or additional credit to demand deposit accounts, prepaid cards, and existing lines of credit of a customer based on expected tax refund amounts. The new or additional credit being, for example, based on a computerized estimate of the tax refund of the customer. The existing line of credit, for example, is adjusted based on the expected refund and/or actual tax refund determined to be available, which can serve as an additional source of repayment for the line of credit. One or more of several adjustments may then be made to an existing line of credit: the line of credit may be increased; fees reduced; or the terms of payment adjusted.