davidw covered it well. To add to his point: I knew about the ASF problem 18 months ago - I work in agriculture and so I follow the news there more closely than the average person. If I had done some thinking about it I would have been able to make some small bets over a year ago - they would have turned out to have great payoff. Of course I would have also made some small bets that didn't pay off - but they would have still been okay because the small bets with the great return would have still paid off about the S&P500 average and as a smart investor I would always diversify my risk.