It’s been awhile since I updated the rolling total returns for the S&P 500 Index*.

I’ll do a follow-up with some different information but right now I wanted to show you the following charts. Here is how I put the following charts together:

• I have montly total return data for the S&P going back to January 1926.

• To calculate the holding period average rate of return, I took the product of the monthly returns and then raised it to 1/n (1 over the number of years).

**Example:** For the 5-year period from 1926 – 1930, the product of the monthly returns was 1.486667021. I then raised it to 1/5 or .2 to get 1.082536981. Then I subtracted one from that to get an average annual rate of 8.25%. Then I ran the calculation for the following month, which would include February 1926 – January 1931. Make sense?

• Then I took those returns and put them in a chart.

As you look at the charts, notice how as the holding period increases, the returns become less sporadic. Also, notice how the 1, 5, and 10-year holding periods all have period of negative average annual returns. the 10-year holding period was pretty solid until the internet bubble, 911, and the housing bubble/credit crisis.

**The S&P 500 Index consisted of 90 stocks prior to February 1957.*

Certainly interesting charts. The missing aspect if you want to understand the S&P I think is demographics though. Take the long run charts and pull out growth due to changes in the working population size and see where that leaves the average.

The reason that’s relevant is because the US working population size is about to shrink for 15 years.