This paper looks at why some countries use the euro as their currency for international trade. By analyzing a lot of data and using a panel model, the researchers found that being in the EU makes a country more likely to use the euro for trade. The euro is becoming more popular, but the U.S. dollar is still used more. Countries with unstable money and similar products prefer using the U.S. dollar. But if the euro's value goes up and down a lot, more countries might start using it. Countries with a lot of power in the global market and those in the euro area are more likely to use the euro for trade.