A paper published by a business professor ten years ago made this point emphatically.
The evidence from 15 international equity markets and over 160,000 daily returns indicates that a few outliers have a massive impact on long term performance. On average across all 15 markets, missing the best 10 days resulted in portfolios 50.8% less valuable than a passive investment; and avoiding the worst 10 days resulted in portfolios 150.4% more valuable than a passive investment. Given that 10 days represent less than 0.1% of the days considered in the average market, the odds against successful market timing are staggering.”
The odds of getting out of the market at just the right time and then getting back in at just the right time are roughly the same as winning the lottery.
This points out the reason why creating a portfolio that will allow you to invest for the long term is essential to creating wealth. You can achieve a decent return and sleep well at night. But in order to do this your portfolio has to match your personal risk tolerance (your Risk Number), one that differs with different people.
We are in a long-term Bull Market, but Bear Markets follow Bulls as night follows day, and some day the Bear will return. That’s when having a properly diversified, risk-tolerant portfolio pays off. Big time.