Trade in intermediate goods is an important feature of trade in developed small open economies. We show that a model that assumes trade in intermediate goods brings the dynamics of an otherwise standard small open economy closer to what is observed in the data. With trade in intermediate goods, movements of international relative prices affect the economy through an additional channel, denoted the “cost channel.” A model embedding this channel comes closer to business cycle data in several dimensions compared to models with trade in final goods only. It increases the share of output variance explained by foreign shocks, lowers the exchange rate pass-through, and delivers a positive international correlation of outputs. In addition, the matching of other business cycle moments is at least as good as in a model with trade in final goods only.