Take a look at some of Wednesday's midday movers:
Caterpillar - The maker of tractors and other agricultural equipment declined after reporting sales fell from April to June.
EMC - The provider of data storage gained after it said it would accelerate its buyback program and raised its profit forecast for the current year.
General Dynamics - The provider of aerospace and defense products rose after reporting a better-than-expected quarterly profit.
GlaxoSmithKline - The U.K. drug manufacturer declined after lowering its 2014 outlook.
Hawaiian Holdings - The operator of Hawaiian Airlines rose after posting better-than-expected second-quarter earnings.
Norfolk Southern - The railway fell after its CEO told analysts Wednesday that rules expected to be proposed by the U.S. Department of Transportation limiting train speed would disrupt rail business.
Northrop Grumman - The weapons maker edged higher after raising its 2014 earnings forecast.
Puma Biotechnology - The drug developer soared after its breast-cancer drug yielded positive clinical results.
Talisman Energy - The Calgary-based oil producer rose after saying it had been approached about "various transactions" by Spain's Repsol SA.
Twenty-First Century Fox - The media and entertainment conglomerate declined after Cowen downgraded it to underperform from outperform. The firm also downgraded Time Warner and Viacom.
Xoom -The provider of money transfers fell after saying could post an adjusted loss in the third quarter.
Yum! Brands - The fast-food operator pulled slightly ahead after its China division stopped doing business with the supplier at the center of a meat scandal.
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—By CNBC's Rich Fisherman.
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