The net asset value of the fund is the balance of the total market value of the fund assets after deducting liabilities at a certain time, which represents the rights and interests of the fund holders. The net asset value of a fund unit refers to the net asset value of the fund represented by each fund unit.

Net unit value = (total assets-total liabilities)/total number of fund units, in which total assets refer to all assets owned by the fund, including stocks, bonds, bank deposits and other securities; Total liabilities refer to liabilities arising from fund operation and financing, including expenses payable to others and interest payable on funds. The total number of fund shares refers to the total number of fund shares issued at that time. Cumulative net value = unit net value after the establishment of the fund+cumulative unit dividend amount. The net fund value is not the main basis for choosing a fund, but the future growth of the net fund value is the key to judge the investment value. The level of net worth is not only influenced by the management ability of fund managers, but also by many other factors. If the fund has been established for a long time, or has grown rapidly since its establishment, the net value of the fund will naturally be higher; If the fund is established for a short time, or the entry time is not good, the net value of the fund may be relatively low. Therefore, if only the current net value of the fund is used as the standard of whether to buy the fund, the wrong decision will often be made. Buying a fund depends on the future growth of the net value of the fund, which is the correct investment policy. Net growth rate and cumulative net growth rate are both indicators to evaluate fund returns. The net growth rate refers to the growth rate of the fund's net assets in a certain period (such as one year), which can be used to evaluate the performance of the fund in a certain period; Cumulative net growth rate refers to the growth rate of the current net value of the fund relative to the net value when the fund contract takes effect, which can be used to evaluate the performance of the fund since its formal operation. Cumulative net growth rate refers to the percentage increase or decrease of fund net value (including dividends) over a period of time. According to the requirements of the CSRC, the calculation formula of the fund's net growth rate is today's net growth rate = (today's net value-yesterday's net value)/yesterday's net value. If there is dividend on that day, the growth rate of today's net value = [today's net value-(yesterday's net value-dividend)]/(yesterday's net value-dividend). The net value used in the above calculation is the current net value, not the accumulated net value. If the cumulative net value is used to calculate, the trouble of dividend treatment can be avoided, but the calculation result has certain error with the above standard result. Since 1970s, the growth rate of fund net value and accumulated net value have become the commonly used evaluation indexes of internationally renowned fund evaluation companies and fund investors, which are used to judge the investment level of fund managers. Among them, when calculating the growth rate of fund net value, if the fund pays dividends in the current period, the fund net value will decrease, so the dividend amount must be added back to the fund net value at the end of the period. In the case of no dividends, the cumulative net growth rate of the fund is equal to the net growth rate since the establishment of the fund; In the case of dividends, it is necessary to calculate the net growth rate of each time period with each distribution point as the boundary (the dividend amount should be added back to the net value of the fund at the end of each period), and then calculate the cumulative growth rate of the whole time period, so as to consider the dividend factor.