S&P 20-Year Rolling Period Returns (1926 – 2008)

Okay, here is an updated version of a post I did a couple of years ago where I took the returns for the S&P and analyzed them by various rolling-periods (5-years, 10-years, and 20-years). Today, I want to look at 20-year rolling-period returns. Check out the graphic I prepared (you can click on the graphic to see a larger version):

S&P Index 20-Year Rolling Period Returns (2008)

It’s incredible just how skewed results can become due to one bad or good year. Notice how 2008’s -37% return dropped the average annual return over the last 20 years to 5.60% (note that these returns include inflation).

Here are some other interesting findings:

0 The number of 20-year periods that had a negative return.

64 The number of periods that had a positive return.

403.02% The average TOTAL return of all the 20-year periods.

$50,302 The average amount (after inflation) that $10,000 grew to over each 20-year period.

$130,946 The most $10,000 would have grown to during a 20-year period.

$11,082 The smallest amount that $10,000 would have become over each 20-year period.

5 thoughts on “S&P 20-Year Rolling Period Returns (1926 – 2008)”

  1. I think you meant to say “20-year period” instead of “5-year” period for the average/most/smallest that $10,00 would’ve grown to. Otherwise a good write-up. Any chance you can give us the average compound return for the entire dataset — I think this number has historically been 9% or so.

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  3. Its kind of amazing how bad the market was betweeen 1955-1993, considering that much of this time the economy was growing quickly, and the middle class were doing very well. Inflation adjusted the market never broke 5.17% (only once) and usually was in the 1-2% inflation adjusted range. I can see why people thought equities were dead in the late 80’s. Considering the ‘conservative assumptions’ of today-say 5% inflation adjusted, if you started work in 1955, you would have been in serious trouble at retirement.

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