Here's a look at stocks in the S&P 1,500 index that displayed unusual volume in Wednesday's trading session.
S&P 500: Trading volume in MEMC Electronic Materials is up 300 percent over its 10-day average, as the solar wafer manufacturer joined a rally in the solar complex on reports that prices for panels and other products were stabilizing.
S&P MidCap 400: Hill-Rom volume jumped 500 percent over its 10-day average, after the medical-technology company said preliminary revenue figures for the latest quarter were lower than expected, forcing it to lower its 2012 outlook.
S&P SmallCap 600: Synnex volume rose 500 percent over its 10-day average, as the information-technolgy firm reported better-than-expected fourth quarter earnings results.
Here is a look at other companies displaying high volume.