Hi all,

Recently I downloaded the S&P 500-index prices from 1950-today (

https://finance.yahoo.com/quote/%5EGSPC/history/) to do some analyses. I began with trying to replicate the numbers presented in the MMM blog post 'Dude, where’s my 7% Investment Return?', taken from chapter 14 of 'A random walk down wallstreet'.

I started with all 1-year holding returns: the percentage gained/lost by buying the index at a 'Close' price and selling 1 year later. The most extreme values resemble those presented in the blog post: -44.76% loss (buy 2008-02-01, sell 2009-02-01) and 52.94% gain (buy 1982-06-01, sell 1983-06-01).

However, when I calculate the 5-year holding returns the numbers start to divert: -35.8% total or -7.16% annual loss (buy 2004-02-01, sell 2009-02-01 ), 219.91% total or 43.98% annual gain (buy 1994-12-01, sell 1999-12-01).

Am I misinterpreting the original analysis? Is the difference in me not accounting for inflation or dividends? Has anyone else tried to reproduce these numbers? 'A random walk down wallstreet' speaks of 'common stock' values rather than the S&P500-index, but I can't imagine the values to differ this much.