The new mediocre. Christine Lagarde, head of the IMF, had it right when she lowered global growth prospects today and called global prospects "mediocre."  There was nothing mediocre in the stock market's action. Ending on the lows. Four to one declining to advancing stocks. Volume heavy.  What has happened is that we have nervousness about the global growth outlook colliding with the certainty the Fed will be tightening sometime in the future.  There was some hope that sell pressures we have seen from Europe would abate once that market closed at 11:30 AM ET, but that didn't happen.  Read MoreS&P 500 lands at 8-week low; Europe slowdown weighs  Right now, it doesn't feel like anyone is missing a lot by staying out of the market, but remember this is a seasonally weak period, and so far it is following the traditional pattern.  But in a few weeks we will be entering a seasonally stronger period.  Generally, selling off going into earnings season has been a buying opportunity in the past.  As for earning season, predictably, companies--and analysts--have been lowering estimates, so the bar once again is low going into the season. We are expecting roughly 6 percent earnings growth from the S&P 500, and if past trends hold we will end up with roughly 10 percent growth.  Read MoreWhy are sell-side stock market analysts so wrong?  Right now, we may not get the beat rate we got in Q2, but it's unlikely earnings will miss.  It's critical now for corporations to clarify the global growth picture, particularly those with exposure to Europe and Asia. I've said it several times: we are going to get positive comments on the U.S. outlook, but for multinationals with exposure to Asia and Europe the commentary will be much more cautious.  Global industrial have reflected that concern. Deere (DE), with nearly 40 percent of its revenues outside the U.S., closed at a 52-week low.
Stocks close at the day's lows as worries about growth outside of the U.S. and fears the Fed may raise rates soon weigh.