This paper outlines the business reasons and provides guidance for developing a legacy modernization strategy. 
We will discuss the choices to be made and outline the key steps involved in creating an application modernization strategy. Along the way, we examine real-life modernization stories. Because we focus on the impact of legacy modernization on business rather than on the technical implementation, no detailed technical knowledge is required. Perhaps the single most important fact to note is that most organizations with mainframe-based systems are spending about 75 percent of their development resources simply to maintain existing applications, which leaves only 25 percent of their development resources for innovation. Effecting a 25-percent reduction in maintenance costs means that investment in innovation can be almost doubled.