The purpose of this study is to examine the effects of a measured aggregate productivity shock on asset returns. To achieve this, a simple equilibrium business cycle model is presented to show that an aggregate productivity shock can be identi?ed as a factor affecting asset returns. The paper uses the Solow residual to measure productivity changes, but deviates from standard practice by incorporating variations in capital utilization rates. The paper ?rst develops the theoretical link between productivity shocks and asset returns with no adjustment costs, and then tests that link with the two measures of productivity, the Solow residual with and without variation in capital utilization. Results based on U.S post-war data show signi?cant differences in the dynamic impacts of these two measures of productivity. The VAR evidence suggests that technology changes, measured with variation in capital utilization, have a delayed impact on asset returns, a distinct ?nding. Finally, policy implications of the ?ndings are discussed.