In 2009 Iranian banks account for about 40 percent of total assets of the world's top 100 Islamic banks. Three of the leading four Islamic banks are based there; Bank Melli Iran, with assets of $45.5 billion came first, followed by Saudi Arabia's Al Rajhi Bank, Bank Mellat with $39.7 billion and Bank Saderat Iran with $39.3 billion. "Iranian banks are still the predominant Islamic banking players, holding seven out of the top 10 ranks and 12 of the 100," the Asian Banker research group reported.  According to CIMB Group Holdings, Islamic finance is the fastest-growing segment of the global financial system and sales of Islamic bonds may rise by 24 percent to $25 billion in 2010.

Commercial banks

Commercial banks are authorized to accept checking and savings deposits and term investment deposits, and they are allowed to use promotional methods to attract deposits. Term investment deposits may be used by banks in a variety of activities such as joint ventures, direct investments, and limited trade partnerships (except to underwrite imports). However, commercial banks are prohibited from investing in the production of luxury and nonessential consumer goods. Commercial banks also may engage in authorized banking operations with state-owned institutions, government-affiliated organizations, and public corporations. The funds received as commissions, fees, and returns constitute bank income and cannot be divided among depositors.