Corporate profit margins may be narrowing down with the S&P 500 index declining more than 20%. The stock market being overly dependent on wide profit margins is vulnerable. Statistics and various calculative methods show us that the six-decade average profit margin of corporate America is 6.3%. If corporate profitability reverted back to its average, it is likely that S&P 500 would be on its way down.  The stock market would have single digit growth. Way out could be P/E expansion and widening of corporate profit-margins. Opinions differ; many proponents believe the stock market will be affected no matter what the level of corporate profit margins. To know more, follow the link: http://www.marketwatch.com/story/investors-need-to-face-the-possibility-of-a-great-reset-2015-05-20