Net interest margin (NIM): Just as we calculate and measure performances of non-financial companies on the basis of their operating performance (EBITDA margins), the performance of banks is largely dependent on the NIM for the year. The difference between interest income and interest expense is known as net interest income. It is the income, which the bank earns from its core business of lending.
As such, NIM is the net interest income earned by the bank on its average earning assets. These assets comprises of advances, investments, balance with the RBI and money at call. As such it is calculated as,
NIM = (Interest income - interest expenses) / average earnings assets
Operating profit margin (OPM): A bank's operating profit is calculated after deducting operating expenses from the net interest income. Operating expenses for a bank would mainly be more of administrative expenses. The main expense heads would include salaries, marketing and advertising and rent, amongst others. Operating margins are profits earned by the bank on its total interest income. As such,
OPM = (Net interest income (NII) - operating expenses) / total interest income
Cost to income ratio: Be it a bank or a manufacturing firm, controlling overheads costs is a critical part of any organisation. In case of banks, keeping a close watch on overheads would enable it to enhance its return on equity. Salaries, branch rationalisation and technology upgradation account for a major part of operating expenses for new generation banks. Even though these expenses result in higher cost to income ratio, in long term they help the bank in improving its return on equity. The ratio is calculated as a proportion of operating profit including