If you are a US or Aussie investor, here's two reasons NOT 'sell in May and go away'

In the US November has historically been the best month of the year for the S&P500, with an average gain of 2.3%, that's based on the last 30 years of data. In the month of May the average return is 0.5%, followed by a return of 0.13% in June and 1.4% in July on average.

Over the last 20 years the saying 'sell in May and go away’ becomes even more useless and WRONG, because if you listened to this silly rule of thumb, and sold your US stocks in May, you could be missing out on the S&P500' s best month of year, which has been July, where the S&P500 has gained 2.3% on average.

Well the best month of year is historically April, with an average +2.1% gain, using the last 30 years of data. In May the average return is -0.75%, followed by a return of -0.12%. So if you sold your Aussie shares in May, you would be selling when the market is historically falling, and you would be missing out on one of the strongest months of the year, July. In July you typically see the ASX200 gain 1.45% on average. That's based on the last 30 years of data.

But looking at the return over the last 20 years, the saying ‘sell in May and go away’ becomes even more useless. The ASX200's best month over the last 20 years, has been July, with an average +2.1% gain. So if you sold in May when the market was -0.9% on average you would be missing out the strongest returns of the year that are ahead.

Again, I think investors would best be served developing their own strategy and investment targets.