Buying a foundation loses money, mainly by buying high and selling low. For example, if you buy when your net worth is high and sell when your net worth is low, you will lose money. Therefore, it is best for funds to buy low and sell high in order to make money.

For example, a fund with a net value of 1 yuan bought 1 ,000 yuan. After long-term holding, the net value of the fund has increased to 2 yuan. At this time, you can get 20 thousand yuan from selling it, and then deduct some expenses. This time, buying a fund can still be profitable. However, if you buy when the net value is 2 yuan and sell when the net value is 1 yuan, the fund will lose money.