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S&P 20-Year Rolling Period Returns (1926 – 2008)
By JLP | September 18, 2009
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):
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.
Topics: Investing, S&P 500 Index | 5 Comments »











September 18th, 2009 at 4:06 pm
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.
September 18th, 2009 at 4:27 pm
Through 2008, the average annual rate of return on the S&P is 9.62% or 7.18% adjusted for inflation.
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September 24th, 2009 at 6:34 pm
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.
September 25th, 2009 at 12:58 pm
Would love to see the numbers through 2009 when available! Might cheer some of us up a little.