Decomposing the year-to-year changes in the earnings distribution from 2004 to 2013, we analyze the role of the employer in explaining earnings inequality in the United States. Movements between the bottom, middle, and top involve 20.5 million workers each year. Another 19.9 million move between employment and nonemployment. There are large gains from working at a top-paying firm for all skill types. Working for a high-paying firm produces benefits today, through higher earnings, that persist through an increase in the probability of upward mobility. High-paying firms facilitate moving workers to the top of the distribution and keeping them there.

Being hired into a job depends not only on one’s own skill but also on that of other applicants. When another able applicant applies, a well-suited worker may be forced into unemployment or into accepting an inferior job. A model of this process defines over- and underqualification and provides predictions on its prevalence and on the wages of mismatched workers. It also implies that unemployment is concentrated among the least skilled workers, while vacancies are concentrated among high-skilled jobs. Four data sets are used to confirm the implications and establish that the hiring probability is low when competing applicants are able.