Input Sourcing and Multinational Production

I propose a general equilibrium framework where firms decide whether to outsource or integrate input manufacturing, domestically or abroad. By outsourcing, firms may benefit from suppliers' technologies, but pay mark-up prices. By sourcing intrafirm, they save on mark-ups and pay possibly lower foreign wages. Multinational corporations arise when firms integrate production abroad. The model predicts that intrafirm imports are positively correlated with the mean and variance of the firms' productivity distribution and with the degree of input differentiation. I use the model to quantify the US welfare gains from intrafirm trade, which amount to about 0.23 percent of consumption per-capita. (JEL D21, F12, F23, F41, L11, L24)