Dell is trying to reassure shareholders about its proposed $24.4 billion acquisition by a group led by its founder, saying it considered a number of strategic options before agreeing to the deal.
Shares of LinkedIn Corp. jumped more than 10 percent before Friday's opening bell after the online professional-networking service reported better-than-expected fourth-quarter results.
Shares of Allstate Corp. on Thursday rose to their highest level since September 2008 on news that the company posted a surprise fourth-quarter profit despite hefty losses related to Superstorm Sandy.
Coventry Health Care's fourth-quarter earnings jumped 39 percent, as the health insurer's enrollment in Medicaid coverage and Medicare prescription drug plans helped counter rising costs.
Reflecting gains in financial markets, investment manager KKR & Co.s fourth-quarter profit grew as it marked up the value of the companies and other assets it owns, and earned more fees from them.