On Tax Over-Shifting in Wage Bargaining Models

Abstract

It has frequently been noted in the wage bargaining literature that increasing average labour taxes may in fact be over-shifted in the pre-tax wage that is negotiated between unions and firms, raising workers post-tax wages. In this paper, we study the precise conditions for such tax over-shifting to occur under both Nash and Right-To-Manage bargaining structures, and considering both competitive and imperfectly competitive output market conditions. In the case of competitive output markets, we derive and interpret the conditions for over-shifting to occur and show that they hold for an entire class of commonly used production functions. Moreover, under monopolistically competitive output markets we show that tax over-shifting will occur when the firm has sufficient market power. The conditions on the production function, that were necessary and sufficient for tax over-shifting to occur under perfect competition, are shown to be no longer necessary. These findings hold for all bargaining structures considered.