A structured approach to legacy banking system modernization at enterprise scale

Legacy Banking Systems must be upgraded. Large banks today rely upon core systemsdeveloped decades ago. Those systems are expensive to support and difficult to change. This means that banks need to modernize their legacy banking systems so they can be agile, resilient and cost-effective. In this paper, a systematic approach to migrating large legacy systems has been identified. Drivers have been defined with both the structure and operation of legacy systems and have surveyed migration methods and have developed a quantifiable cost model to associate migration design with expense. This paper also provides decision-making matrices and tables to guide in the selection of strategy and identify "best practices" for implementing such strategies such as automation of development and operations, cost management of finance, testing and governance. The analysis includes specific enterprise examples and references to peer-reviewed research and industry reports. Key takeaways are to perform modernization in a physical and use detailed financial models to measure the potential value of migration.