Search, Concave Production, and Optimal Firm Size

This paper presents a simple search and bargaining economy in which firms use concave production. Because a firm and worker negotiate over the worker's marginal productivity, the firm's wage is a function of its labour force. Reacting to this wage function, firms choose an excessively large and inefficient number of workers. They overemploy, but because too few firms exist in equilibrium, aggregate employment and vacancies are suboptimal. Imposing a fixed exogenous wage, for example by legislating a minimum wage or through union contracting, reduces this inefficiency.