Direct investment is incorporated into a simple general equilibrium model of international trade. The analysis focuses on an attempt to endogenize the internalization decision. It is argued that a reasonable approach assumes that arm's length contracts must be “simple” so that “complex” arrangements require internalization. The model relates direct investment to the degree of underlying uncertainty and to fundamental trade determinants, such as relative factor endowments. The behavior of the model contrasts sharply with that of the Markusen-Helpman model, which takes internalization for granted.

This paper rehabilitates the old wage price spiral. It shows that, after an increase in aggregate demand, the process of adjustment of nominal prices and nominal wages results from attempts by workers to maintain or increase their real wage and by firms to maintain or increase their markups of prices over wages. Under continuous price and wage setting, the process of adjustment would be instantaneous; under staggering of price and wage decisions, the adjustment takes time. The more inflexible real wages and markups are to shifts in demand, the higher is the degree of price level inertia, and the longer lasting are the effects of aggregate demand on output.