Extensive literature demonstrates that workers with high tenure suffer large and persistent earnings losses when they are displaced. We study the reasons behind these losses in a tractable search model that includes a lifecycle dimension, endogenous job mobility, and worker- and match-heterogeneity. The model jointly explains key characteristics of the U.S. labor market such as large average transition rates, a large share of stable jobs, and earnings losses after displacement. We decompose earnings losses and find that only 50% result from wage loss, and endogenous reactions and selection account for the remainder. These findings have important implications for welfare costs of displacement and labor market policies.