Unusual Volume Leaders: Gilead Sciences Spikes

Comstock | Getty Images

Trading volume in Gilead Sciences jumped 260 percent on Friday over its 10-day average, after the biopharmaceutical company reported positive results from an early clinical trial of a recently acquired hepatitis C drug.

Here's a look at other stocks in the S&P 1,500 index that displayed unusual volume in the trading session.

S&P MidCap 400: Dresser Rand volume increased 480 percent over its 10-day average, as the manufacturer of gas turbines lowered its fourth-quarter revenue outlook.

S&P SmallCap 600: STR Holdings volume rose 600 percent over its 10-day average, after the maker of components for the solar industry forecast a fourth-quarter loss.

Follow Giovanny Moreano on Twitter:@giovannymoreano