It's Not The Economy

"Despite the general contention that the economy and the stock market are inexorably connected, the facts get in the way of confirming common wisdom.
This chart presents the average stock market return and average GDP growth by decade and by secular bull/bear market cycle.
Economic growth is not the primary driver of stock market returns; stock market returns are driven primarily by a cycle in the P/E ratio (see the Secular Cycles chart above). Although economic growth does increase the denominator in the P/E (earnings), actual returns are generally the result of trends in the P/E ratio. This and other research that Crestmont has conducted dispels this conventional notion. "

http://crestmontresearch.com/pdfs/Stock%20Economy.pdf