Earnings Responses to Social Security Contributions

Abstract

This paper exploits discontinuities induced by earnings caps for social security contributions (SSC) in Germany to analyse the effect of SSC on gross labour earnings. Empirical evidence is based on two complementary approaches utilising two administrative data sets. First, employment responses to SSC at the intensive margin are identified by a modified bunching approach that is applied to kinks in the budget set generated by the earnings caps. Second, I exploit an increase of a regional earnings cap of health and long-term care insurance as a natural experiment. In order to analyse economic incidence a difference-in-differences approach is used to estimate the effects on gross earnings. I find employment responses to be negligible and the burden of SSC to be shared equally between employers and employees. Both results turn out to be robust and are consistent with a competitive labour market model.