Checkable or demand deposits represent money deposits in a commercial bank with the right of the owner to withdrawal upon demand. Various forms of equivalent arrangement are now possible at savings banks, credit unions and even securities dealers. They bear different names such as NOW, SDA and ATS.
The bulk of the transactions in any modern economy is completed by check writing. In businesses in particular, the use of coins and bank notes is often referred to as petty cash and is reserved for miscellaneous minor expenses (such as buying a present for the birthday of an employee).