Take a look at some of Thursday's midday movers:
Cummins moved lower after the diesel engine maker cut its full year forecast, citing weak demand in international markets and a stronger dollar.
DuPont rose after being halted on news that the firm named Edward Breen and James Gallogly to its board. Trian, which nominated its own slate for the board, said it refused to consider any proposal that didn't include Nelson Peltz.
Aegerion Pharmaceuticals moved higher on news Sarissa Capital took a 5.8 percent stake in the company.
Sony traded higher after the entertainment group lifted its full-year forecast.
Becton Dickinson gained ground after posting better-than-expected quarterly results.
Costco fell after Deutsche Bank downgraded the stock to "hold" from "buy" and lowered its price target to $142 from $147, citing forex and gas headwinds over the next year.
Cemex surged after the cement company posted a 31 percent increase in fourth-quarter operating earnings. The firm also targeted 2015 capital expenditures of $800 million.
Ball Corp traded higher following the company's statement relating to the possible acquisition of its UK rival Rexam. Ball is a supplier of metal packaging to the beverage, food, personal care and household products industry.
W.R. Grace rose on its plan to split the company in two.The chemical maker emerged from bankruptcy in 2013.
Prudential Financial moved lower after the life insurer reported lower-than-expected quarterly earnings as expenses rose and the financial services company booked losses from a weaker Japanese yen.
Sprint gained ground after its quarterly revenue fell less than expected and the mobile services company attracted more subscribers by cutting prices and offering promotions.
GrubHub surged after the online food-order-and-delivery company reported a better-than-expected 49.5 percent rise in quarterly revenue as more diners used its services to order meals.
Macy's declined after Morgan Stanley downgraded the stock to equal-weight from overweight and removed it from its Best Ideas List, based on price.
Nu Skin slid after reporting a near 63 percent drop in quarterly profit as revenue more than halved in greater China, the firm's biggest market.
Groupon moved higher on reports the deals website is in talks to seal a majority stake in its South Korean e-commerce company, Ticket Monster.