Rm usually takes the industry average, and the common reference is S&; P500 index, Standard & Poor's; P The average return on investment of each company in 20 years is 10. How many years of national debt is used for Rf depends on what you need to do with it. Take the interest rate of the corresponding maturity national debt. For example, if you want to evaluate the expected return on investment of a five-year project, choose the interest rate of five-year government bonds. If it is necessary to value the company, take a longer one, such as the interest rate of 20-year government bonds.

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National debt (national debt; Government loan, also known as national bond, is a creditor-debtor relationship formed by the state on the basis of its credit and in accordance with the general principles of debt. National debt is a bond issued by the state, a government bond issued by the central government to raise financial funds, and a debt certificate issued by the central government to investors, which promises to repay the principal and interest within a certain period of time. Because the issuer of national debt is the country, it has the highest credit and is recognized as the safest investment tool.

China's national debt refers to the national debt issued by the Ministry of Finance on behalf of the central government. Guaranteed by the national financial reputation, the credibility is very high. It has always been called "Phnom Penh bond", and cautious investors like to invest in government bonds. There are three kinds of bonds: voucher bonds, bearer bonds and book-entry bonds.

On June 15, 2020, the Ministry of Finance issued a notice, clarifying that special anti-epidemic treasury bonds will be issued in 2020. In September, FTSE Russell announced the inclusion of China government bonds in FTSE government bond index.