A natural holdup problem arises in a market with search frictions: firms have to make a range of investments before finding their employees and larger investments translate into higher wages. In particular, when wages are determined by ex post bargaining, the equilibrium is always inefficient:...

External certification of workplace skills obtained through on-the-job training is widespread in many countries. This may indicate that training is financed by workers, and certification serves to assure the quality of the training offered by the firm. However, other evidence shows that general...

A "folk theorem" originating, among others, in the work of Stiglitz maintains that competitive equilibria area always or "generically" inefficient (unless contracts directly specify consumption levels as in Prescott and Townsend, thus bypassing trading in anonymous markets). This paper...