Bonds are fixed income securities. When the market interest rate rises, the coupon rate of the bond is fixed. Relatively speaking, the attraction is reduced and the yield is reduced. The yield of bonds is divided into interest and bid-ask spread. The interest has not changed, the buying price has not changed, the selling price has changed, and the yield has changed. If the coupon rate of a bond is 3%, the market interest rate rises from 2.75% to 3%, the coupon rate of the bond cannot be changed, and its appeal to investors decreases, then the price of the bond will fall. Theoretically speaking, the increase of market interest rate means that the rate of return required by the market has increased, but the interest of bonds is fixed and cannot be increased, so the rate of return will be relatively reduced.