10 most profitable companies in the world The accounting income follows the historical cost principle and the matching principle, which is conducive to the objective reflection of the business management responsibility of the enterprise management authorities. But, due to the historical cost principle inherent defects, especially according to the present value of revenue and expenses by historical cost line, makes the calculation of accounting earnings lack of inner logical unity, and the matching principle is difficult to carry out, so that the book value of assets can not reflect its real value, cost cannot be fully compensated. And the economic benefit is measured in the current value, which reflects the actual value of the asset, which is beneficial to the full compensation of the cost. With the real success of the trump tax reform bill, investors in the short term focus more on whether the market has already digested this benefit. But to increase political accountability and to sacrifice the independence of the central bank is to throw the baby out of the bath. Monetary policy is complex and technical. Handing control to politicians is more prudent than handing over keys to the country's nuclear power plants.