Definition:

Net Interest Income (NII) is the difference between the revenue generated from a bank's interest-bearing assets and the expenses associated with paying on its interest-bearing liabilities. It is a key measure of a bank's profitability.

Examples

1. A bank earns interest from loans and mortgages and pays interest on savings accounts and certificates of deposit. The difference between these interest amounts is the Net Interest Income.
2. If a bank earns $5 million from loans and pays $2 million on deposits, the NII is $3 million.

Formula:

Net Interest Income = Interest Earned on Assets - Interest Paid on Liabilities

How to use the metric:

Net Interest Income is used to assess a bank's core profitability from its lending and deposit activities. It helps in evaluating the effectiveness of a bank's interest rate risk management and its ability to generate income from its primary business operations.

Limitations:

1. NII does not account for non-interest income sources, such as fees and commissions.
2. It can be affected by changes in interest rates, which may not reflect the bank's operational efficiency.
3. It does not consider credit risk or the quality of the bank's loan portfolio.

Applies to:

Net Interest Income is most applicable to the banking and financial services industries, where interest income and expenses are significant components of the business model.

Doesn't apply to:

NII is not applicable to industries that do not primarily deal with interest-bearing assets and liabilities, such as manufacturing, retail, or technology, because these sectors do not rely on interest income as a primary revenue source.

Summary:

Net Interest Income is a crucial financial metric for banks and financial institutions, reflecting the profitability of their core lending and deposit activities. While it provides insights into interest rate management and operational efficiency, it has limitations, such as excluding non-interest income and being sensitive to interest rate fluctuations. It is primarily used in the banking sector and is not relevant for industries outside of financial services.