Financial Insights

The Uncommon Average

The US stock market has delivered an average annual return of around 10% since 1926.1 But short-term results may vary, and in any given period stock returns can be positive, negative, or flat. When setting expectations, it’s helpful to see the range of outcomes experienced by investors historically. For example, how often have the stock market’s annual returns actually aligned with its long-term average?

Exhibit 1 shows calendar year returns for the S&P 500 Index since 1926. The shaded band marks the historical average of 10%, plus or minus 2 percentage points. The S&P 500 Index had a return within this range in only six of the past 93 calendar years. In most years, the index’s return was outside of the range—often above or below by a wide margin—with no obvious pattern. For investors, the data highlight the importance of looking beyond average returns and being aware of the range of potential outcomes.

1 As measured by the S&P 500 Index from 1926–2018.

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