The reasons for fixed investment in a fund to buy less when it rises and buy more when it falls are as follows: Fixed investment will increase investors' holding costs when the fund rises, and at the same time, it will also increase investors' risks; while fixed investment during the fund's decline, through continuous

Buying and increasing the share of positions will reduce investors' holding costs, diversify risks, and achieve a smile curve effect when the fund rebounds.

In addition, investors do not need to set stop-loss levels when making fixed investments in funds, but they can set stop-profit levels to realize part of their profits.