Financial institutions are exposed to a highly dynamic environment that is characterized by an intense competition and short technological hype cycles. Against this background, the assimilation of on-demand computing infrastructures as particularly Grid and Cloud computing can be assumed to be a potential strategic response to address fast changing market and technological demand as well as to comply with arising mimetic pressure between competitors. So far, little empirical research has been conducted to assess the influence of environmental dynamics on the assimilation process of on-demand computing infrastructures. Grounded in the Technology-Organization-Environment framework, this article proposes a holistic perspective emphasizing the environmental determinants of Grid assimilation for the asset management process and analyzes its consequences for IT value generation. The derived hypotheses were tested based on 103 responses from senior IT decision makers of financial services providers that have already adopted Grid technology for their asset management process. The results from partial least squares analyses indicate that in particular environmental dynamics determine the assimilation of Grid-based infrastructures. Our results contribute to IS assimilation theory by integrating environmental dynamics into the Technology-Organization-Environment framework.