Systems, computer program products, and computer-implemented methods apply or otherwise 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. A computerized estimate of the tax refund available from a tax return of the customer is formed. A portion of the computerized estimate of the tax refund which can be made available as the line of credit is then determined. The existing line of credit is then adjusted based on the expected refund determined to be available, which will 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. The invention may be implemented as a computerized process, a computer system or a computer program product.