This article develops and tests a random coefficient two-index model for commercial bank stock returns which controls for the time-varying interest rate sensitivity caused by a bank's changing maturity profile. Using a sample of 51 actively traded commercial banks, the seemingly unrelated regression results provide evidence that commercial bank stock returns are significantly interest rate sensitive. The effect of interest rate changes on bank stock returns is found to be positively related to the maturity mismatch between the bank's assets and liabilities, when the proxy for interest rate changes and the proxy for maturity mismatch are compatible to each other.