Micron Technology - The memory chipmaker rose, a day after reporting fiscal third-quarter results that beat expectations.
Vertex Pharmaceuticals - The company's shares rallied after studies showed a combination of its drugs met the goals of two late-stage clinical trials in patients with cystic fibrosis.
Read MoreVertex cystic fibrosis combo meets study goals
Walgreen - The drugstore chain fell after reporting third-quarter revenue below Wall Street's estimates.
xG Technology - The company gained after saying it had been chosen as a subcontractor to provide communications and network services to the U.S. Army.
(Read More: See CNBC's Market Insider Blog)
—By CNBC's Kate Gibson
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