QAB stands for Quarterly Average Balance, which is a requirement for certain savings accounts. It is the average of all the closing day balances for any quarter. The QAB is calculated by adding the closing day balances and dividing the sum by the number of days in the quarter. For example, if the QAB of an account is Rs. 10,000, it means that on average, the account holder needs to maintain Rs. 10,000 daily, but not necessarily every single day. The QAB requirement is met if the average balance maintained over the quarter is equal to or greater than the QAB, and no penalty would be imposed for non-maintenance of QAB. The minimum QAB varies across banks and locations, and banks keep changing the limits, so it is important to know the QAB requirement from your bank. If the account holder fails to maintain the minimum QAB, the bank may charge a maintenance fee or impose a penalty.