For holding periods less than one year that is a true statement. However, for longer holding periods of many years that is not true as long as the investment is decent. As holding periods increase the odds go to 100% that the price is above the original purchase price. At 100% accuracy the real risk goes to zero because you never have a loss.

Most “investors” are actually traders because their holding period is on average only 6 months. Over the past 70 years the average investor has underperformed the S&P by 5% per year. The cause is primarily from diversification into underperforming assets and stock prices in the short term are about equally likely to fall as rise. An increase in volatility causes an increase in risk.

For a buy and hold strategy, the risk goes to zero and the reward increases with volatility. The key here is to hold great long term holdings like cap weighted ETFs. These constantly change what they own so that you always have the best investments.

The financial services industry approach of restricting price volatility to reduce risk has consistently produced underperformance versus the S&P of 5% per year. The Stars buy and hold strategy with no such restrictions has outperformed the S&P by a factor of 17 over the past 26 years.

If you allow the portfolio to rise and fall you can make a fortune. If you don’t your returns suffer greatly.