buying and selling used cars for profit British Glass is organising a one-day seminar on funding for decarbonisation and energy efficiency work on Thursday 2 November (north of England, venue TBC) – which will be attended by British Glass members’ and non-members. Interest rate, in the form of expression, refers to the ratio of the amount of interest to the total amount of borrowed capital in a certain period of time.  the interest rate is the interest level per unit time of the unit currency, indicating the interest rate. Economists have been looking for a theory that can fully explain the structure and change of interest rates. Interest rates are usually controlled by the central bank of the country and administered by the federal reserve board in the United States. Today, interest rates are one of the important tools for macroeconomic regulation. In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: 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.