A banking institution is of the same fiber as the ordinary industrial enterprise, subject to the same ills, responsive to the same treatment. In the industrial plant, cost of units of production must be known in order that a profit may be realized. Likewise in a bank, the cost of units of service must be found, to the same end. In manufacturing, each customer's order must bear its own proportion of expense, and in banking each customer's account should bear its pro rata share of the cost of operation. If, then, a banker can by some means test an account to see if it is bearing its rightful amount of costs, he will be able to separate the unprofitable from the profitable accounts. With these clearly classified, he is in a position to take such steps as may be advisable toward converting the losers into income producers. To supply such a test is the main purpose of a bank cost accounting system.
Arizona Corporation Commission, "Cost accounting system for a bank" (1922). State Publications. 72.