Does inequality react to stabilization policies and macroeconomic shocks at business cycle frequencies? Does an unanticipated innovation in inequality impact aggregate demand and drive cyclical fluctuations? Does the level of inequality influence the propagation of stabilization policies? To answer these questions, I first investigate which factors of earnings distributions are represented by a measure of inequality in Chapter 1. Chapter 2 develops an econometric tool to evaluate the contribution of macroeconomic shocks to the dynamics of an endogenous variable of interest. Finally, Chapter 3 deals with the questions above.In Chapter 1, I derive principal components of log earnings distributions in the U.S. and propose a simple three-factor...