The ‘unspent margin’, or total money balances, is made of the consumers’ and traders’ balances taken together. From this, he derives a form of the quantity theory. Hawtrey argues that traders’ balances are relatively stable, and thusthe supply of money (in a wide sense taken to include credit) and consumers’ income and outlay are concerned with the operational relationships. Compared to the Cambridge income-based approach, his places greater emphasis on the demand for nominal balances rather than real balances. Keynes used a similar balances approach to the quantity theory, after 1925, leading up to the "Treatise on Money" (1930), in which he distinguishes first between investment and cash deposits and later between income, business and savings deposits.