I want to hear what others are thinking about this. I am changing my tactics from diversification to buying only one ETF and running with it. Look at the attached file. You have USA, Europe, Latin America and Asia broad markets in there. You will notice that they all follow same pattern. The only difference is in risk/return. Bigger gains, larger the losses of course, but that doesn't matter here since it follows the same pattern. For example: If I would to invest in all ETF's in the picture my average return would be 60%. If i was to invest in only ILF (Latin America index) my average return would be 120%. Why then diversify when all of the markets are following same pattern. You might say you need to diversify to cushion the blow but you will also cushion the returns so it doesn't really matter. You can also use same timing methods(inflation, fed rates, sentiment, macd, technicals or whatever you use) as for trading s&p 500 since all of these ETF's are following s&p 500 as it seems. I am seriously considering concentrating on only one ETF and forget about stock picks while the market is in the bull mode. This way it is much more simple with higher probability of return and it takes way less time to research. You can even use best 6 months strategy combined with macd or moving averages. Any comments are appreciated.