I often get questions about whether it’s a good time to invest when the markets are reaching new highs. Look at the illustration of the S&P 500 below from Dimensional Fund Advisors. On average, when the market closes at a monthly high, it is even higher over 80% of the time in the next one,three,and five years. What is particularly interesting is that the number is almost the same as if the index did not hit a new high. I don't know about you but I can't see much difference between the two. For the long term investor, there's no reason to try to time the markets.