Bilateral output synchronization in a globalized world: A macroeconomic evaluation of the third-country effect

This paper examines the influence of third countries on the output synchronization between two trading partners. We first address this issue in a three-country Dynamic Stochastic General Equilibrium model, where trade in intermediate goods operates at the intensive and extensive margins. We find that adding a third trading partner strengthens the output co-movement between two countries through two channels: a trade channel, driven by a higher total number of varieties traded that makes production processes more homogeneous across countries, and a macroeconomic channel where the third country exerts a stabilizing effect on the intensive and extensive margins of production in the other two countries. Applying Jordà's local projections to 34 countries from 1979Q2 to 2019Q4, we find that the inclusion of a third partner raises the output co-movement in 75% of cases on average, with a median rise of 54% on average compared to the two-country case. Our results are robust to (i) an alternative identification of productivity shocks and (ii) the inclusion of extensive trade margins as control variables. Those stylized facts of upward output synchronization resulting from the explicit inclusion of a third trading partner are consistent with our theoretical predictions.