Energy, specifically crude oil is an imperative factor in determining stock market success. The price of oil has more than doubled over the past twleve months, and historically, a doubling in oil prices has thus far always predicted a recession for the following twelve month period. Remember the importance of oil, even for non-commodity investments.

Source: http://seekingalpha.com/article/220206-energy-the-single-most-important-factor-for-your-investments?source=hp_wc