The first essay examines emerging market non-financial firms' decision with respect to the use of foreign exchange instruments. Firms use foreign debt for hedging and speculation in the long-term. They use currency derivatives more in order to adjust the long-term speculative and hedging positions and less in order to speculate in the short-term. Given the increasing number of firms being traded in multiple markets, the second essay focuses on documenting and explaining the puzzling persistent spreads in stock returns of the same firm across different markets. It suggests that spreads are as importantly affected by market microstructure differences as by relative investor sentiment. The third essay documents and explains significant variations of firms' exchange rate exposure between developed and emerging markets. It shows that country specific factors account for about 30% of the variability of firms' exposure and that higher domestic financial market sophistication allows firms to decrease their exposure.