Used in asset/liability management to describe the difference between rate-sensitive assets and rate-sensitive liabilities in rate gaps or between cash inflows and outflows in liquidity gaps.
See gap. American Banker Glossary
* * *
1) A difference between the length of time for which money is borrowed and the length of time for which it is invested, or the difference between the maturities of borrowing and investments. One example is when a bank borrows money for a short time but lends it for a longer period, so there is a mismatch between its source and use of funds.
2) A mismatched book, or a mismatch in an overall trading position, occurs when short and long positions do not complement each other.
Financial and business terms. 2012.