From the Novel Investor:
The chart below shows several issues investors struggle with all the time. It’s difficult to pick the best performing investment year after year, yet for many investors it’s an annual event. They look for an encore, picking the best asset class last year with the hope of a repeat performance. Yet, betting on last year’s winner rarely works out.

Assets at the top of the chart one year could be at the bottom the next, and vice versa. Much of this is due to reversion to the mean. But over the long-term, those big swings even out. The chart shows annual returns for eight asset classes against a diversified portfolio. Diversification works to smooth out those big swings in the short-term. While you’ll never get the biggest gains of any year, you avoid the huge losses.

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The chart above ranks the best to worst investment returns by asset class over the past 15 years.

Source: Novel Investor