Check out which companies are making headlines before the bell:
Keurig Green Mountain–Keurig Green Mountain will replace WPX Energy in the S&P 500, while WPX will take Keurig Green Mountain's spot in the S&P MidCap 400. S&P made several other index changes, with Biogen Idec (BIIB) replacing American Electric Power in the S&P 100, although American Electric will remain in the S&P 500. The changes will take place after the close on March 21.
Baker Hughes–Goldman Sachs upgraded the oilfield services company's stock to "buy" from "neutral", on increases in capital spending and a recovery in pricing power.
Lorillard–Goldman Sachs upgraded the tobacco company's stock to "buy" from "neutral", citing what it anticipates will be a period of more limited regulatory risk.
GNC Corporation–Credit Suisse downgraded the health products retailer's stock to "neutral" from "outperform", based on lower potential for strong comparable store sales growth and lower Gold Card membership renewal rates.
JA Solar–The solar equipment maker reported fourth quarter profit of 16 cents per share, 15 cents above estimates, with revenue topping estimates as well. The company said its results were helped by a more stable pricing environment, as well as ongoing cost reduction efforts.
Hertz Global–The company is preparing to spin off its construction equipment rental business, according to the Financial Times. The move–which would value the unit at an estimated $4.5 billion–is expected to be announced this week.
Berkshire Hathaway–The company is urging shareholders to vote against a proposal calling for Warren Buffett's company to use some of its cash on a "meaningful" dividend. The proposal comes from shareholder David Witt, who will offer it at the May 3 annual meeting. Berkshire has not paid a cash dividend since 1967.
Encana–The energy firm is in talks to sell its Wyoming natural gas fields to private equity firms Carlyle Group and NGP Energy Capital Management for about $2 billion, according to the Wall Street Journal.
Toyota–The Japanese auto giant has locked out 6,400 workers at two plants in India, as a dispute over wages escalates, and allegations emerge about threats against management.
—By CNBC's Peter Schacknow
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