Software failures can lead to substantial costs for the user. Existing models for software reliability prediction do not provide much insight into this financial impact. Our approach presents a first step towards the integration of reliability prediction from the IT perspective and the business perspective. We show that failure impact should be taken into account not only at their date of occurrence but already in the design stage of the development. First we model cost relevant business processes as well as the associated IT layer and then connect them to failure probabilities. Based on this we conduct a reliability and cost estimation. The method is illustrated by a case study.