State Bank of India (SBI) is offering various types of savings accounts including a zero balance saving account where monthly average balance (MAB) rule is not applicable. Monthly Average Balance (MAB) is the sum of all end of the day (EOD) closing balance divided by the number of days in that month. Zero balance saving account doesn't require customers to maintain any particular minimum average balance, according to SBI's website- sbi.co.in. Despite this, the bank provides all the usual facilities that come with a regular savings account.