Timing the markets is hard; perhaps, impossible. But it is easy to see that market prices widely swing.
In this essay, I describe the investing performance of past and current value investors. As you will shortly read, all legendary investors reported poor results at times. The active investor should know that even great investors failed to correctly time markets.
For the passive investor, I bring the historical record of indices such as the S&P 500 and the Dow Jones. Here, my goal is to show you that if history is any evidence of the future, then markets swing in price.
So if you invest in an active mutual fund or an exchange-traded fund (ETF), unless you can calmly withstand market swings, you are best to buy assets that do not have a daily market quotes.
Even great investors reported paper losses . The legendary Walter Scholls wrote to investors of a 5% loss in 1957, followed by a 9% loss in 1969 and an 8% loss in 1970.
During 1973 and 1974, Scholls reported a loss of 15% during each of those two years; Sequoia fund, another legendary fund, reported a loss of 38% during those years. Even Charlie Munger lost over 53% .
Let's fast forward to current examples. Between July 2007 and June 2008, Mohnish Pabri lost 32%, and in the following year, he suffered an additional 25% paper loss. In other words, in two years, the market value of a $100,000 investment was halved.
Pabrai, whom I admire and who much influences my thinking, also reported a loss of 22% in June 2012. So let the record show that even great minds experience bad years.
Another investor whom I consider to be one of the greatest is Guy Spier. In 2008, he reported on a 47% loss and a 16% loss in 2015. He writes in The Education of Value Investor :
"2008 was something else. I'd never experienced an avalanche like this within my portfolio. The serious damage began in June when the fund fell by 11.8%. The following month, I was down another 3.5%. And then things started to get ugly. In September, it tumbled by another 12.5%. For the year as a whole, I was down 46.7%. On paper, almost half of my shareholders' money and my family's money had gone up in smoke."
(To clarify: by no means is this an attempt to embarrass Pabrai or Spier. The goal here is to show you that it is a certainty that you will see paper loss if you invest in the stock market. Whether you invest on your own or let others manage your money.)
The next section is for readers who are disinterested in neither investing on their own nor in a fund. This section is for those who choose to invest in the stock market using ETFs.
If you were bullish  on the United Stated economy and, say, a decade ago placed a $100,000 bet in an ETF that tracks the performance of the S&P 500 index, the value of your position would now be $271,000.
And compounded growth of about 12% over ten years may now affect your expectation levels. Yet it is unlikely you will get double digits return from a single-digit growth economy.
In Bull!, Maggie Bahahr shows why. She provides three examples of market cycles. First, between 1882 and 1897, 15 years, the S&P 500 total return was 3.4%. Between 1903 and 1921, 18 years, the total return was 0.6%. More recently, the S&P 500 annual return between 1967 and 1982, 15 years, was 0.2%. And between 2000 and 2004, the annual total return was negative 5%.
Can you imagine the frustration of parting with cash for 15 to 18 years only to realize that you are no better off than when you started?
Not only do market cycles affect return, but the annual return also affects the investor's psyche. For example, between 2000 and 2003, the S&P 500 lost value. If you had $100,000 in the stock market, the value of your portfolio would be $60,000 three years after. In 2008, the market lost that same amount of value in a single year - the S&P 500 lost 38% in 2008.
Both the Dow Jones Industrial Average and the Russell 2000 show similar results. Between 2000 and 2003, the Dow lost 28% in total, and in 2008 it lost 34%. The Russell 2000 dropped 21% in 2012 alone and 35% in 2008.
There is little we can do to stop, delay, or change the natural swings of markets. But two things are in our control. First is an awareness. Knowing that you will have a significant paper loss at some point should leave you less troubled when the day arrives. You will know that this too shall pass [ 4] .
Secondly, keep cash handy. It is one thing to see the market price of your portfolio drop - yet it is terrific when price declines allow you to buy great businesses at excellent prices.