Abstract
Substantial literature has been produced on the increasing wage gap in the United States, invoking various possible factors, but largely ignoring the relationship between firm size and wage distribution. In this study, the author decomposes wage differences over time between large, medium and small firms, identifying the effects of observed characteristics (and their returns) along with residual inequality, i.e. inequality among workers with the same observed characteristics. From 1992 to 2012, trends at small, medium and large firms became more uniform, while wage inequality rose across the board. Significantly, it increased more quickly in the upper half of the wage distribution and at large firms, where residual inequality was highest.