Financial services providers are exposed to different sources of institutional pressure arising from the intensive competition and regulation in the banking sector. Against this background, Grid technology assimilation can be seen as a potential strategic response to increasing requirements in terms of complex new financial products, the assessment of arising risks, and sophisticated investment strategies. However, so far little empirical research has been conducted to quantify the determinants of Grid assimilation in the financial services industry. Grounded in the technology-organizationenvironment framework, this article provides a holistic perspective on the determinants of Grid assimilation and the role of institutional pressure in the assimilation process. The derived hypotheses were tested based on 197 complete responses from IT decision makers of financial services providers that already have implemented Grid technology. The results from partial least squares analyses suggest a strong positive impact of mimetic and normative pressure on Grid assimilation, but surprisingly do not support the hypothesized strong relationship of coercive pressure on Grid assimilation. The derived and validated conceptual model contributes to the diffusion of innovations and IS assimilation theory by further integrating institutional theory into the technology-organizationenvironment framework.