What are the macroeconomic forces behind the cross-sectional and time-series variation in expected excess returns? To answer this question, this paper integrates models of empirical asset pricing with structural vector autoregressions (VAR). First, I use an unconditional asset pricing framework to construct an orthogonal shock in a macroeconomic VAR that best explains the cross-sectional variation in expected returns. The obtained “λ-shock” closely resembles identified monetary policy surprises and does not explain the recent US recessions. Second, I integrate return-forecasting methods to construct a second shock in the VAR, which best explains time-variation in expected returns. The obtained “γ-shock” turns out to be virtually orthogonal ...