Stock index futures sold off hard early in the session following a drop of 5% in the Shanghai Composite Index.  Currently the indices look tired and overplayed to the upside.  Although buying has been coming in on the breaks, the rallies have all be labored. 

The 50% price for the week in the September E-mini S&P 500 is 974.00.  This price acted like major resistance earlier in the trading session.  If this market cannot penetrate this level late in the session then look for a test of the overnight low at 964.00.

One major clue as to whether this rally is finished for the time being will be a break of the previous day's low by the September E-mini NASDAQ.  This price is 1581.50.  A break through this level late in the session will likely trigger a sharp acceleration to the downside.

Weakness at the midsession has been triggered by poor auction results.  Trading volume appears to be down but is expected to pick-up after the release of the Fed Beige Book at 1 pm Central Time.