Usually, Class A shares agree on a certain expected annualized rate of return according to certain rules, such as one-year time deposit +3%, and the net value of the parent fund after deducting the net value of Class A shares is the net value of Class B shares. The share ratio of A and B of stock-based graded funds is generally 1: 1. Most parent funds are index funds that passively track an index. For example, the tracking target of Penghua CSI A-share resource industry index grading fund is CSI A-share resource industry index.