It is inevitable that the interest rate of corporate bonds is higher than that of national bonds. Government bonds are guaranteed by government credit and have a high credit rating. Corporate bonds are the company's credit, and there are credit risks, so credit risk compensation is needed. The interest rate of corporate bonds with high credit rating will be lower than that of corporate bonds with high credit rating, because the credit risk of corporate bonds with high credit rating is small. Generally speaking, national debt is considered as a risk-free bond and is considered to have no credit risk. The interest rate difference between other bonds with the same maturity and national debt is the credit spread.