Normally light volume on a pullback can be regarded as a good thing. When the pullback is fairly large and the volume is extremely light the expectations can turn bearish. For instance, the S&P dropped about 1.5% today on the lightest volume since July 3rd. I loosened the parameters slightly to get a decent sized sample and ran a study:

Of course volume this week and next week are expected to be a bit lighter due to traders taking vacations. Still, I don’t find the results terribly encouraging for the bullish case over the next two weeks.