In the turbulent world of e-commerce, companies can only survive by continuously reinventing their business models. However, because most studies look at business models as snapshots in time, there is little insight into how changing market-related, technological and regulatory conditions generally drive revisions in business models. In this paper, we examine which types of external drivers are strongest in forcing business models to change throughout their life cycle. To do so, we study 45 longitudinal case descriptions on business model dynamics of (networks of) organizations in various industries. The results of this survey indicate that technological and market-related forces are the most important drivers of business model dynamics, while regulation plays only a minor role. In particular for start-ups, the effect of technological and market-related drivers is the strongest in the early stages of a new business model, while the effects are modérate over time for established, large companies. Our results provide clues to practitioners on what external factors to take into account in different stages of business model design and redesign.