Independence is more difficult in an age when cross-border spillovers of national monetary policy become powerful. These spillover effects make central Banks consider the impact of their policies on foreign and global systems. But it is difficult to pursue global goals when the central bank operates under the narrow, centralized mandate of its independence, and is close to impossible. 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. This article discusses the easiest way the best client billing software on your business. First, you must learn your preferences. What are you searching for currently billing software? Second, do you require a desktop application or a web-based program? Third, is the time tracking system software user-friendly? Fourth, how affordable is the time and expense software? Under the theoretical framework of the theory, the theory of commodity market equilibrium and the monetary market equilibrium of Keynesian theory are unified. Marx's theory of interest rate decisions from the perspective of the source and essence of interest, taking into account the institutional factors in the role of interest rate decisions of interest theory, its theoretical core is the interest rate is determined by the average profit margin. Marx believed that under capitalism, interest is a part of profit and a form of conversion of surplus value. 1. Principles of securities investment