NYSE

J.C. Penney Co. Inc., down $2.08 at $22.25

The department store chain said that Michael Francis, an executive brought in to help redefine the brand, is leaving the company.

Walgreen Co., down $1.87 at $30.09

The drugstore chain said it will pay $6.7 billion in cash and stock for a stake in European pharmacy retailer Alliance Boots.

Barnes & Noble Inc., down 61 cents at $14.63

The bookseller and Nook e-reader maker said that its fourth-quarter loss narrowed but was still wider than analysts expected.

Chesapeake Energy Corp., up $1.04 at $18.71

An ally to activist investor Carl Icahn will join the energy company's board this week as Icahn pushes for a leadership shake-up.

Nasdaq

Microsoft Corp., up 86 cents at $30.70

In an attempt to take on Apple Inc.'s popular iPad, Microsoft announced a new tablet computer it calls "Surface."

Sonic Corp., up 28 cents at $9.17

A Sterne Agee analyst upgraded the fast food company's stock rating to "Buy," citing its new ads and improved products.

Network Equipment Technologies Inc., up 14 cents at $1.32

Internet hardware and software maker InSonus Networks said that it is buying the communications equipment maker for $41.3 million.

Citi Trends Inc., up $1.90 at $15.64

A Susquehanna analyst