Check out which companies are making headlines before the bell:
Tiffany—The luxury goods retailer cut its guidance for the full year ending January 31, now seeing earnings of $4.15 to $4.20 per share following a "disappointing" holiday season. Its guidance was below both Tiffany's prior estimate of $4.20 to $4.30 and current analyst consensus of $4.33 per share.
Lululemon—The yogawear maker raised its current quarter guidance, saying it now expects to earn 71 cents to 73 cents per share; that compares to its prior guidance of 65 to 69 cents and Street estimates of 69 cents. Lululemon credits "improving trends and strong holiday results."
Dollar Tree—The discount retailer said it expects to reach an agreement with the Federal Trade Commission on its proposed purchase of rival Family Dollar by the end of January. The retailer also said it expects it will need to divest fewer than 300 stores to make the deal happen. Separately, Family Dollar sent a letter to shareholders reiterating its recommendation that shareholders favor the Dollar Tree deal over a rival proposal from Dollar General.
Caesars Entertainment—A group of the casino operator's bondholders have filed papers to force its operating unit into involuntary Chapter 11 bankruptcy. Caesars has been trying to win creditor support for a restructuring program.
Morgan Stanley—JMP Securities downgraded Morgan Stanley to "market perform" from "outperform" on a valuation basis, following outperformance over the past three years.
D.R. Horton—KeyBanc upgraded the homebuilder's shares to "buy" from 'hold," saying it would outgrow its peers by focusing on lower-priced homes.
NPS Pharmaceuticals—The New Jersey-based drugmaker agreed to be bought by Britain's Shire for $5.2 billion in cash. NPS specializes in drugs for rare diseases.
Burlington Stores—The retailer raised its guidance for current quarter revenue and earnings, following a better-than-expected holiday season. Burlington also said its Chief Financial Officer Todd Weyhrich is retiring, to be replaced by Executive Vice President Marc Katz.
HCA—HCA said its 2014 results will be better than it had previously expected, as it experienced a jump in admissions and emergency room visits. The hospital operated is scheduled to report its latest results on February 3.
Chesapeake Energy—Goldman Sachs upgraded Chesapeake to "buy" from "neutral," pointing to a new management that's using capital efficiently.
AOL—Cowen & Co. downgraded AOL to "market perform" from "outperform" on a valuation basis. Cowen said it is moving to the sidelines now that the stock is near its target price, despite what it calls an improving asset portfolio for AOL.
J.C. Penney—The retailer will take a total of $38 million in charges to close about 40 of its stores. It said $21 million in charges will be taken for the fourth quarter of fiscal 2014, with the rest to be booked later.
General Motors—The automaker will unveil the newest version of its Chevy Volt hybrid at the Detroit auto show today.
Foundation Medicine—The Los Angeles-based drug maker will have Roche Holding as a new majority owner, as the Swiss company buys a stake of up to 56.3 percent in Foundation for up to $1.18 billion.
Best Buy—The electronics retailer's shares could rise 20 percent this year, according to an article in this weekend's Barron's, which said Best Buy will be helped by a significant upgrade cycle for televisions.
SunEdison—The solar equipment maker and India-based Adani Enterprises will invest up to $4 billion in a joint venture that would be one of the country's largest solar panel makers.
Tekmira Pharmaceuticals—The firm is buying Pennsylvania-based OnCore BioPharma, creating a combined company with a value of about $750 million.
Bristol-Myers Squibb—The pharmaceutical giant reported positive results from a late-stage study involving lung cancer treatment using its "Opdivo" drug.