Traditionally, the core functions of banking were to (1) accept money from, and collect checks for, customers; (2) honor checks for orders drawn on them by customers; (3) keep current accounts, or something of that kind, in which customers’ debits and credits are entered; and, of course, (4) lend. Banks derived their income largely from the margin between the interest rates they paid on money deposited with them and the interest rates they charged on money lent by them.
Strictly speaking, the calculation of income demands complete revaluation of all assets and obligations at the end of every period. Practically, the question is: How shall the requisite value estimates be obtained?
In the long run, the business unit or source will yield more revenue to the public treasury than the individual; and the place where the income is earned will derive larger revenues than the jurisdiction of the person.