In concentrated labor markets, where workers have fewer employers to choose from, employers may exploit their monopsony power by contributing less to workers' health benefits. This study examined if labor market concentration was associated with higher worker contributions to health plan premiums. We combined publicly available data from the Census to calculate labor market concentration and the Medical Expenditure Panel Survey Insurance/Employer Component to determine premium contributions from 2010 to 2016 for metropolitan areas. After controlling for year fixed-effects and market characteristics, we found that higher labor market concentration was associated with higher worker contributions to health plan premiums, lower take-home income, and no change in employer contributions to premiums, consistent with the hypothesis that greater labor market concentration is associated with less generous health benefits. When evaluating the effects of mergers and acquisitions on labor markets, regulatory agencies should critically assess worker contributions to health insurance premiums.
Keywords: employer-sponsored insurance; health insurance premiums; labor market concentration; private insurance.