The basic economic unit of society in the primitive society of the clan, tribe, slave owners in the slave society, feudal society's family and the manual workshop, after the evolution of the form of this modern form in a capitalist society was born enterprise. The optimal combination of benefits and risks is the best combination of benefits and risks. If the benefit is certain, the risk is minimized; To read more Diversification of securities, the establishment of a scientific and effective portfolio of securities; Based on the above two kinds of comparison and analysis of the concept of earnings, reveals the inadequacy of accounting earnings, i.e., the accounting income does not take into account inflation, the production gains, goodwill to improve the impact of changes and their value, and can be found on only the pursuit of reliability, and can be measured, which affect the enterprise's profit ability and continuous operation ability. Accounting, since the 1950 s began to pay attention to absorb the income concept of some reasonable kernel of economics, the concept of modern accounting theory of income in the income concept of economics.