Industry leading media investment management company GroupM decided it needed to take a new approach to data management and analysis to better support its clients. About two years ago, the firm undertook a modern development project to deliver a central data repository and chose Microsoft .NET and Microsoft Visual Studio to develop the mission-critical solution because Microsoft could deliver on the whole spectrum of technologies needed, including databases, security, identity management and modern user-interfaces. GroupM chose to build GMCore as a domain oriented n-layered application meaning that Domain-Driven Design (DDD) principles were followed along with a Service Oriented Architecture (SOA) for the applications.