Openness to trade as a determinant of the macroeconomic elasticity of substitution

Several theoretical and empirical studies on economic growth consider the macroeconomic elasticity of substitution between capital and labor as a measure of economic flexibility that depends on technological as well as institutional aspects. One institutional aspect of economic flexibility is openness to trade. I examine in a Heckscher-Ohlin model with two large countries trading intermediate goods how openness affects the elasticity of substitution. If the technology has a constant elasticity of substitution in a closed economy, opening up to trade raises the elasticity of substitution only in the country that accumulates capital at a faster rate.