Check out which companies are making headlines before the bell:
Depomed–Horizon Pharma offered to buy its rival drug maker in an all-stock deal valued at $29.25 per share. That represents a 42 percent premium over yesterday's closing price for Depomed, which has rejected past overtures from Horizon.
Lululemon–Guggenheim named the yoga wear maker's stock as its "Best Idea," citing strong same-store sales growth and continuing momentum.
Tesla–Deutsche Bank lowered its rating on the automaker to "hold" from "buy," saying it's still bullish on the development of Tesla's battery systems technology but that the shares already reflect that opportunity.
Salesforce.com–Brean Capital upgraded Salesforce to "buy" from "hold," based on a growing opportunity to upsell customers on its newest cloud-based services.
Tiffany–Bernstein upgraded Tiffany to "outperform" from "market perform," pointing to an improving consumer environment and more attractive "entry point pricing" for its silver jewelry category.
Fitbit–Baird began coverage on the wearable device maker with an "outperform" rating, saying current consensus estimates on the Street could prove conservative in the wake of ongoing sales momentum.
Shake Shack–Morgan Stanley downgraded the restaurant chain to "underweight" from "equal weight." The firm said that while Shake Shack is executing well, the level of optimism surrounding the company is not supported by market fundamentals.
Advanced Micro Devices–The chipmaker cut its current quarter guidance because of weak personal computer demand. AMD expects second quarter revenue to be down eight percent from the first quarter compared to the prior forecast for a three percent drop.
Advance Auto Parts–Advance Auto Reports will join the S&P 500 after the close of trading Wednesday. The auto parts retailer replaces Family Dollar Stores, which has been acquired by S&P 500 member Dollar Tree.
Sony–Sony will get a $14.7 million dollar investment from Yahoo Japan for its Sony Real Estate venture. Once the deal is complete, Sony will own 56.3 percent, while Yahoo Japan will own 43.7 percent.
Nike–Nike struck a deal to outfit the University of Michigan's sports teams beginning with the 2016-2017 season, replacing Adidas. The new contract will extend through at least 2027, with an option to extend further to 2031.
General Electric–GE said it would take a $16.1 billion after-tax charge related to its GE Capital exit plan, accelerating the timing of the expected charges that it had previously revealed.
Walt Disney–Disney is at the center of an Anaheim City Council meeting today, with members voting on whether to approve plans for a $1 billion expansion of its Disneyland complex. As part of that plan, Disney would keep a special tax exemption for 30 more years beyond its currently scheduled expiration on June 30, 2016. Separately, Atlantic Equities upgraded Disney to "overweight" from "neutral" based on the potential for earnings growth.
Wingstop–Jefferies began coverage on the restaurant chain with a "buy" rating, saying its focused menu and appeal to specific ethnic groups could help it stand out in a crowded fast casual field.
Sunedison–The utility company's TerraForm Power unit will buy wind farms located in the U.S. and Canada from Invenergy Wind for $2 billion