This paper explores currency choice at the level of the firm. We posit that how a firm invoices in one market affects its invoicing decisions in other markets. To support this claim, we first show that a sizable fraction of exporters use multiple currencies to trade. We then show that a firm’s invoicing decision in one market is predicted by that firm’s invoicing decisions in other markets. To interpret this evidence, we build a quantitative model of currency choice in multiple markets allowing for spillovers across markets. We plan to show how complementarity effects are quantitatively and qualitatively important determinants of the cross-section of invoicing currencies, as well as undertake counterfactuals.