The article explores why some countries' currencies are used more in global financial transactions. They found that when two countries trade a lot or have big economies, their currencies are more likely to be used in each other's financial markets. Also, if the destination country has a well-developed financial market or shares a common language with the source country, the currency is more likely to be used. The study suggests that for the Chinese currency, the Renminbi, to become a true international currency, it should be used more in the financial markets of the US and UK.