The strategic role of IT and its significance throughout the organization increases complexity, variety, and the need forchange. Hence, IT management must deal with uncertainties derived from different, conflicting, and ever-changingdemands. In this sense, Enterprise Architecture (EA) is playing an increasingly important role in improving ITmanagement practice. If contemporary organizations do not succeed in managing architectural issues, there is a clear risk that considerable resources will be invested without achieving desirable effects. This article investigates how EnterpriseArchitecture Principles impact the management of IT investments in the context of large organizations. The purpose of the article is to provide a deeper insight into the relationship between EA and management of IT investments through theelucidation of two significant types of principles: Delineation (differentiation) principles and Interoperability (integration)principles. Our conclusion is that the choice of architectural principles has a major impact both on alignment betweeninformation systems and business demands, and on the management of IT investments. This impact concerns at least four aspects: the responsibility for IT investments; time to value; long-term alignment; and coordination of investments ininformation systems with changes in business processes.