In the turbulent world of e-business, companies can only survive by continuously reinventing their business models. However, as most literature studies business models as snapshots in time, it is ill-understood how changing market, technology and regulation conditions generally drive revisions in business models. This paper studies which type of external drivers are strongest in forcing business models to change throughout their life cycle. To do so, we survey 45 longitudinal case descriptions on business model dynamics of (networks of) organizations in various industries. According to our results, technology and market forces are most important drivers of business model dynamics, while regulation plays only a minor role. Especially for startups, the effect of technology and market drivers is strongest during the early stages of a new business model, while for established, large companies the effects are moderate over time.