Most types of accounts can be made sub-accounts, but Bank and Cash accounts cannot. Organizations with wholly-owned subsidiaries must process payroll for each subsidiary under its own EIN, so it's not unusual for each subsidiary to have its own series of accounts. It would be nice to be able to group these under umbrella folders, similar to the way that other accounts can be made sub-accounts, so that the bank accounts under one umbrella could be "rolled up" to see the total balance underneath with only a single line item.