Diffusion scholarship expects little adaptation of core elements of policy models. However, the empirical reality is different; diffusion of even highly-regarded models, such as the Silicon Valley venture capital (VC) policy model, results in marked adaptation of the source model. This article asks: why does variance, rather than convergence, characterize the diffusion of the Silicon Valley VC model? The answer to this question lies in conceptualizing policymakers as rational in light of their normative context rather than as wholly rational or bounded learners. I demonstrate why and how the Silicon Valley VC model is necessarily adapted by “contextually rational” policymakers in the geographically, ethnically and economically proximate states of Hong Kong, Taiwan and Singapore. I find that policymakers’ interventionist orientations, private sector financing preferences and international versus domestic firm promotion biases drive contextually rational – and unique – adaptations of the Silicon Valley VC policy model. Policymakers’ norms are central to shaping how the model is translated into local policy action, meaning we can, and should, expect adaptation as a result of diffusion.