Check out which companies are making headlines before the bell on Tuesday:
Medtronic - The medical products maker earned $0.93 per share for its fiscal third quarter, two cents above estimates. The company said it's dealing with a changing health-care environment, but remains committed to delivering dependable growth.
Apple - Apple will be in court today, facing off against investor David Einhorn. Einhorn wants a judge to block a shareholder vote on Apple's proposal to require shareholder approval to issue preferred shares.
(Read More: See the Day's Top Percentage Winners & Losers)
ConAgra Foods - The company is raising its fiscal 2013 earnings forecast to $2.15 per share, putting it above current estimates of $2.13. ConAgra cited contributions from its Ralcorp acquisition, as well as better-than-expected performances from its consumer and commercial foods segments.
Best Buy - Barclays has upgraded the electronics retailer's stock to "overweight" from "equal weight," citing stabilizing sales and cost cuts, as well as founder Richard Schulze's ongoing interest in a buyout.
Wynn Resorts - The casino operator will be allowed to hold a special shareholder meeting this week to oust dissident shareholder Kuzuo Okada from its board of directors. A judge blocked a bid by Okada late Friday to prevent the meeting.
Coinstar - JPMorgan Chase is downgrading the Redbox parent to "underweight" from "neutral," after the company issued what the firm considers a mixed fourth-quarter and weak current-quarter guidance. It cited elevated risks with the Redbox business, among other factors.
Novartis - The drugmaker said its outgoing chairman Daniel Vasella will cancel a deal under which he could have earned up to $78 million for not advising competitors. Vasella will be stepping down at the company's annual meeting later this week and his exit deal had been widely criticized.
Monsanto - Monsanto will be before the U.S. Supreme Court today in a widely followed patent case involving its "Roundup" brand weed killer.
Microsoft - Microsoft will launch Outlook.com today, its new online email service that escalates the fight against rivals such as Google, Yahoo, and AOL. Microsoft's Hotmail and MSN users will be converted to the new service by the summer.
(Read More: Microsoft's Outlook Takes Aim at Google's Gmail)
Burger King Worldwide - The restaurant is issuing an apology after its Twitter account was hacked Monday. The hackers posted obscene messages and changed the account's profile picture to a McDonald's logo.
Express Scripts - Express Scripts earned $1.05 per share, excluding certain items, for the fourth quarter, three cents above estimates, with revenue also slightly above consensus. The pharmacy benefit manager was helped by more use of generic drugs, as well as its acquisition of Medco Health Solutions last year.
Herbalife - Hedge fund manager Daniel Loeb has sold part of his long position in the nutrition company. Sources told CNBC that Loeb began selling a few weeks ago, although he maintains a position in Herbalife.
Google - Google is developing plans to launch retail stores in the U.S., according to The Wall Street Journal. The paper said, however, that it isn't clear when the stores might open.
MGM Resorts - RBC Capital has upgraded the casino operator's stock to "outperform" from "sector perform," pointing to six potential catalysts for 2013 earnings. The catalysts included a potential dividend from MGM China, and a decision from regulators on its regaining its New Jersey gaming license.
(Read More: See CNBC's Market Insider Blog)
—By CNBC's Peter Schacknow
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