We examine the relationship between physician preferences and both the intensity and cost of care delivered to commercially insured heart attack patients. We match survey data on physician preferences, collected by Cutler, Skinner, Stern, and Wennberg (2019) (CSSW), to medical claims data from the Health Care Cost Institute, which spans over 50 million insurance beneficiaries. In contrast to CSSW, who find strong correlations between aggressive practice preferences and both expenditure and utilization for the Medicare population, we find relationships that are both economically and statistically smaller in magnitude within the commercially insured population. Variations in commercial insurers’ prices appear to play an important mediating role.