Take a look at some of Thursday's midday movers:
General Motors rose after news Chairman and CEO Dan Akerson purchased 25,000 more shares of the stock according to a recent government filing.
Robbins & Meyers surged more than 20 percent after the company announced it will be acquired by National Oilwell Varco in a deal valued at $2.55 billion, or about $60 per share. The deal is said to be the largest in a string of acquisitions this year for the oilfield-services equipment maker.
Sprint Nextel traded near 52-week highs on heavy volume after the telecommunications company reported that Keith Cowan, head of strategic planning for the company would be stepping down, effective September 30th.
SunPower shares tumbled after at least four analysts slashed price targets on the solar products company. On Wednesday, the company handed in disappointing earnings guidance for its current quarter.
E-Trade Financial rallied after its board dismissed Chief Executive Steven Freiberg and named its current chairman, Frank Petrilli, as its interim CEO. A search is on for a permanent replacement, according to reports.
—By CNBC's Lori Spechler. Follow Lori on twitter @LoriSpechler