Halloween revisited

Apparently, that "Sell in May and Go Away" has worked ... for many countries over the past umpteen years. Assume that we Buy right after Halloween (on Nov 1) and Sell at the start of May (or the end of April). Then let's compare the Total (cumulative) Return for the (November-to-April) period and the Total Return for (May-to-October) ... over the 10 years (Jan 1, 1999 to Jan 1, 2009) for a number of country Indexes. Note that, for each set, there are 10 years worth of time periods, each 6 months long. Anyway, it'd look like so: Mamma mia! I'm a believer! There's a spreadsheet here: http://www.gummy-stuff.org/Excel/halloween2.xls ------------------------------------- Aah, but does it work for individual stocks (as opposed to country Indexes)? Here's some DOW stocks: