市場下跌時DCA投資方法。

-估計好政治經濟趨勢。這是時刻要進行的。特別每次下單前。

-從適合的起點開始。分時分批進行。

-買關盤價是一個好的選擇。關盤前決定。特別適合共同基金。

-每次的量正比於跌的幅度（也可以非線性）。大掉是買的好機會。沒跌就不加。

-不用馬金。

由於不知道底所以要DCA.

但是可以估計底的範圍。保證有現金。

這是一般方法。隨時靈活發揮。

https://en.wikipedia.org/wiki/Dollar_cost_averaging

In dollar cost averaging, the investor decides on two parameters: the fixed amount of money invested each time, and the time horizon over which all of the investments are made. With a shorter time horizon, the strategy behaves more like lump sum investing. One study has found that the best time horizons when investing in the stock market in terms of balancing return and risk have been 6 or 12 months.^[7]

One key component to maximizing profits is to include the strategy of buying during a downtrending market, using a scaled formula to buy more as the price falls. Then, as the trend shifts to a higher priced market, use a scaled plan to sell. Using this strategy, one can profit from the relationship between the value of a currency and a commodity or stock.[citation need