chapter 7 cost-volume-profit analysis In just three days, the yield on the 30-year Treasury bond jumped 16 basis points, the biggest gain since December 2008. The two-year - 30-year spread widened at the fastest rate since last year's U.S. election. This week the yield curve flattens out. Is it a short adjustment or a bear market start? The principle of rational investment: investment in securities investment in analysis and comparison. Investment in securities provides an important channel for the society to raise funds, which is an effective way for enterprises to raise direct financing. When the economy overheats and inflation rises, interest rates are raised and credit tightened. When the overheated economy and inflation are under control, the interest rate is duly lowered. Interest rates are therefore one of the fundamental economic factors. Interest rates are an important financial variable in economics, and almost all financial phenomena and financial assets have more or less connection with interest rates. Then the interest rate theory of the loan is the interest rate theory of neoclassical school, which is proposed to correct Keynes's theory of "liquidity preference". In some ways, the theory of interest rate can be regarded as a synthesis of classical interest rate theory and Keynesian theory. The diversity of creators and the regulation of innovative and friendly regulation is essential to the establishment of a mechanism for equality and human rights characteristics.