Investors buy funds at low points, with lower cost, higher cost performance ratio, higher expected return, less risk and greater possibility of profit; Investors' high purchase cost is not very cost-effective, with low expected income, high risk and high possibility of loss.

In fund operation, the lower the net value of the fund, the more cost-effective, because the lower the net value of the same fund, the more fund shares you buy, so it is better to buy the fund at a low level.