the profit book With the development of social division of labor and market economy, the concept of market is also developing and deepening, and the multiple meanings of different levels are reflected in the deepening of the project. 3. The role of securities investment Diversification of securities, the establishment of a scientific and effective portfolio of securities; The theory of modern political economy in China holds that the profit under the socialist system is the form of the value of the surplus products created by the workers for the society. The value composition of the product is c+v+m,c+v is converted into production cost, and the m is part of the surplus product created by the laborer for the society, which translates into profit for the enterprise. The specific form of socialist profit is: to realize profit, that is, the balance of the sales revenue of the enterprise minus the expenses of various expenses; To pay the profits in accordance with the provisions to the national financial department; After tax profit, that is, the profit of the enterprise shall be returned to the enterprise in accordance with the state provisions. Economist lynde hull explained that the benefits of capital in different periods of time would be interest. According to linde hull, interest in a specific period and the difference between the expected consumption is savings (during the period of the growth of capital), and returns the sum of consumption and savings are given period of time.