Simple rule to get rich..
Buy lower sell higher.
Sp500 (500 biggest US stocks) is down from 3930 area to 3760 area today, or down 4.3%
Time to sell was at 3930.
I will buy if drops to 3635.
I was mostly all capital preservation in my 401k. I nibbled a little bit today at todays closing price (S&P 500 index fund).
If it drops a few more % points I may buy some more.
I could do fine trading the S&P in my 401k and Fidelity must know it too. If I make more that a few trades within a certain timeframe they suspend my ability to trade for a while.