In a 2021 Forrester Wave™, we researched, analyzed, and scored application modernization and migration service (AMMS) providers, presenting a clear set of global leaders. However, technology leaders must consider additional factors when making a final purchasing decision; for example, your ideal AMMS supplier may be different from your current incumbent applications management service (AMS) provider. Moreover, a few different types of suppliers bring varying value propositions to the task of cloud migration and modernizations. This report discusses the factors to consider when selecting an AMMS supplier.