Evaluate the empirical evidence that employer concentration in labor markets produces wage suppression beyond what competitive markets would produce, quantify the wage penalty attributable to monopsony power across sectors, and assess which policy interventions — antitrust enforcement, non-compete restriction, wage transparency, or sector bargaining — have demonstrated effectiveness in reducing wage suppression.

Review of labor market concentration measurement literature using HHI-based employer concentration indices from BLS QCEW data. Analysis of Azar et al. (2020) cross-metro labor market concentration study. Review of natural experiments from state-level non-compete enforcement variation, minimum wage increases in concentrated versus competitive labor markets, and German sector-level collective bargaining outcomes.

Labor market monopsony — employer market power that enables wage suppression below competitive levels — has moved from theoretical concern to empirically documented phenomenon over the past decade. The evidence is now sufficiently strong to support the claim that monopsony power is a significant contributor to wage stagnation and income inequality in the United States and other economies with declining union density.

Azar, Marinescu, and Steinbaum (2022) provide the most comprehensive measurement: using vacancy data to construct Herfindahl-Hirschman Index measures of employer concentration for 8,000 occupation-metro area combinations, they find that moving from the 25th to the 75th percentile of employer concentration is associated with a 17% reduction in wages, holding worker and job characteristics constant.

At the highly concentrated end of the distribution (HHI above 2500, representing markets effectively controlled by one or two employers), the wage penalty reaches 25-30% below the competitive wage. These are large effects — comparable in magnitude to estimated union wage premiums — and they affect a substantial share of the labor force: Azar et al.

estimate that more than 60% of US labor markets by occupation-metro combination would be classified as highly concentrated under federal merger guidelines applied to product markets.

Non-compete agreements are a distinct but related mechanism of monopsony: they restrict worker mobility between employers, reducing the outside option that disciplines employer wage-setting even in markets with multiple employers.

The FTC's 2024 economic analysis for the Non-Compete Clause Rule estimates that non-compete agreements affect approximately 30 million workers (18% of the US workforce) including low-wage workers in food service and retail where their use cannot be justified by trade secret protection. , cited in FTC analysis).

German sector-level collective bargaining provides an instructive counterfactual. Germany maintains industry-wide collective agreements covering approximately 56% of workers (down from 75% in the 1990s), with IAB data showing that covered workers earn 7-12% more than uncovered workers in comparable roles, and that the premium is larger in highly concentrated local labor markets — suggesting collective bargaining specifically counteracts monopsony wage suppression.

The synthesis finding is that labor market monopsony is both pervasive and under-addressed by current policy. Antitrust enforcement has not been applied to labor market concentration with the same rigor as product market concentration.

Non-compete restriction and wage transparency (which enables wage comparison and improves worker bargaining position) are the interventions with strongest short-term implementation feasibility.

Sector-level bargaining is the intervention with strongest demonstrated effectiveness in reducing wage suppression but requires institutional reform that has not achieved political momentum outside of Europe.