3 Minimum monthly balance indicated must be maintained at the end of each day in the month to qualify for the fee rebate. (td.com)
A more recent example is a minimum account balance fee where a checking or savings account must maintain a average minimum monthly balance or incur a maintenance fee. (stockmonkeys.com)
As of time of writing, the account with the lowest required minimum monthly balance is the aforementioned TD Every Day Business Account. (thebalancesmb.com)