We develop a tractable small‐open‐economy framework to characterize the constrained efficient use of the monetary policy rate, foreign exchange (FX) intervention, capital controls, and domestic macroprudential measures. The model features dominant currency pricing, positive premia on local currency debt arising from financiers' portfolio constraints, and occasionally‐binding external and domestic borrowing constraints. We characterize the conditions under which the traditional prescription—relying solely on the policy rate and exchange rate flexibility—remains sufficient, even in the presence of externalities. By contrast, to manage noise trader flows into and out of the local currency debt market, FX intervention and in some cases capital inflow taxes should be used instead of the traditional prescription. Moreover, if a country faces a mix of local currency premia and external borrowing constraints, we establish that certain regulations to limit FX mismatch may alleviate the external borrowing constraint but exacerbate the local currency premia. Finally, we show that capital controls may dominate domestic macroprudential measures in cases when external shocks trigger stress in domestic housing markets.

We propose a “dominant currency paradigm” with three key features: dominant currency pricing, pricing complementarities, and imported inputs in production. We test this paradigm using a new dataset of bilateral price and volume indices for more than 2,500 country pairs that covers 91 percent of world trade, as well as detailed firm-product-country data for Colombian exports and imports. In strong support of the paradigm we find that (i) noncommodities terms-of-trade are uncorrelated with exchange rates; (ii) the dollar exchange rate quantitatively dominates the bilateral exchange rate in price pass-through and trade elasticity regressions, and this effect is increasing in the share of imports invoiced in dollars; (iii) US import volumes are significantly less sensitive to bilateral exchange rates, compared to other countries’ imports; (iv) a 1 percent US dollar appreciation against all other currencies predicts a 0.6 percent decline within a year in the volume of total trade between countries in the rest of the world, controlling for the global business cycle. We characterize the transmission of, and spillovers from, monetary policy shocks in this environment.