Banks that sell insurance make more money than banks that don’t.

In 2007, commercial banks and savings banks with some insurance-related income had a median net income that was 44% higher than the median net income at banks with no insurance-related income, according to researchers at the Bank Insurance Market Research Group, Mamaroneck, N.Y.

The net income gap was 15% at banks with $10 billion or more in assets, and 40% at banks with less than $250 million in assets, the researchers report.

The ratio of noninterest income to total bank revenue was 14% at all banks and 17% at banks with some insurance-related income.