Using highly disaggregated Korean micro-level trade data, this paper examines the determinants of invoicing currencies and their implications. We find that the determinants of exchange-rate pass-through – intermediated imported inputs, market share, and foreign currency liability – play an important role in shaping currency invoicing decisions. Invoicing choices also exhibit strong persistence over time and strategic complementarity. Demand elasticity further amplifies strategic complementarity. Moreover, exchange-rate pass-through differs markedly across invoicing currencies, with important implications for real economic allocations. The findings here are highly relevant for policymakers in small open economies that do not issue vehicle currencies yet face pervasive dominant-currency pricing.