What is Net Interest Margin (NIM)?
Net Interest Margin is the primary profitability metric for banks and credit unions. It measures the spread between what a financial institution earns on its assets (loans, securities) and what it pays on its liabilities (deposits, borrowings), expressed as a percentage of average earning assets. A credit union with NIM of 3.00% earns 300bp more on its loans than it pays on its deposits. NIM is affected by the interest rate environment, asset mix, funding costs, and competitive dynamics. Participation purchases increase NIM if the participation yield exceeds the institution's cost of funds.
Formula
NIM = (Interest Income - Interest Expense) / Average Earning Assets Typical range: 2.50% - 4.00% for community banks and CUs
How LoanBook Uses Net Interest Margin
LoanBook tracks NIM from call report data in the CRM institution profiles. NIM trends inform opportunity scoring; institutions with declining NIM may be seeking higher-yielding assets (buyer opportunity), while those with rising NIM may have excess earning capacity (seller opportunity).
Frequently Asked Questions
What is a good NIM for a credit union?
The national average NIM for credit unions is approximately 2.80-3.20%. Credit unions with NIM above 3.50% are generating strong spreads; those below 2.50% may face profitability pressure, especially as operating costs rise.
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