Bank Melli Iran is the first national and commercial retail bank of Iran. It was considered as the largest Iranian company in terms of annual income with a revenue of 364 657 billion Rials in 2016. It is the largest bank in the Islamic world and in the Middle East. By the end of 2016, BMI had a net asset of $76.6 billion and a network of 3.328 banking branches; so it was known as the largest Iranian bank based on the amount of assets. The brand of BMI was recognized as one of the 100 top Iranian brands in 10th National Iranian Heroes Championship in 2013. The National Bank has 3328 active branches inside, 14 active branches and 4 sub-stations abroad, and it has 180 booths. The first managing director of BMI was Kurt Lindenblatt from Germany, the first foreign branch of BMI was opened in Hamburg, Germany in 1948.

The rial is the official currency of Iran. It is subdivided into 100 dinars, but due to the rial's low purchasing power the dinar is not practically used. While POS terminals are in use in Iran, the country does not participate in any of the major international card networks due to sanctions between it and the United States. Travelers are instead advised to load money onto a local prepaid card account.