Concentration in US Labor Markets : Evidence from Online Vacancy Data

Using data on the near-universe of online US job vacancies collected by Burning Glass Technologies in 2016, we calculate labor market concentration using the Herfindahl-Hirschman index (HHI) for each commuting zone by 6-digit SOC occupation. The average market has an HHI of 4,378, or the equivalent of 2.3 recruiting employers. 60% of labor markets are highly concentrated (above 2,500 HHI) according to the DOJ/FTC guidelines. Highly concentrated markets account for 20% of employment. For manufacturing industries, we show that labor market concentration is distinct from product market concentration, and is negatively correlated with wages in each industry's top occupation