Abstract: We propose a Neo-Heckscher-Ohlin model of trade that combines comparative endowment advantage, comparative technological advantage, international capital mobility, and trade-specific transaction costs. Unlike competing characterizations, our model is the first of its kind to treat specialization in production endogenously using an inframarginal general equilibrium setting. The results are startling! They suggest that production within the diversification cone – a key assumption of Heckscher-Ohlin theory that is required for its core propositions (such as factor price equalization) to hold – may only prevail on the razor’s edge, or under exceptional circumstances. In addition, our findings nominate a mechanism by which improvements...