(Read More: See the Day's Top Percentage Winners & Losers)
Caterpillar - Goldman Sachs has downgraded the heavy equipment maker to "neutral" from "buy," saying an oversupplied commodity environment means it no longer sees an upside to earnings expectations.
Facebook - Facebook issued a statement saying it welcomes the Securities and Exchange Commission's announcement that companies can use social media to disseminate key information.
( SEC Permits Company Disclosures Using Social Media)
BP - The energy giant is putting its U.S. wind farm operation up for sale. The company did not put a projected value on that unit, but said it expects "attractive offers."
AstraZeneca - The drugmaker is buying privately held U.S. biotech company AlphaCore Pharma for an undisclosed price. AlphaCore is an early stage company that's working on a new type of cholesterol treatment.
(Read More: Pfizer, Novartis, Abbott Weigh Bids for Brazil's Ache: Sources)
Google - Google is reportedly launching a second generation version of its Nexus 7 tablet computer in July, according to Reuters.
Baidu - The China-based search engine company is developing a digital eyewear product similar to Google's Google Glass. Baidu is currently testing the product internally and said it is unclear if the product will ever actually be sold.
BlackBerry - CEO Thorsten Heins told The Canadian Press his company hasn't ruled out another version of the PlayBook tablet, despite the failure of earlier versions to catch on with consumers.
Weight Watchers International - Weight Watchers is paying off outstanding debt with a new loan, a move that will increase its interest costs but will give it more flexibility.
Global Payments - The credit card transaction processor earned $0.87 per share for its third quarter, two cents below estimates, with revenue also short of Street consensus.
Dollar Tree - The discount retailer's stock was upgraded to "overweight" from "equal-weight" at Morgan Stanley, which is raising same-store sales estimates after its research indicated consumers have shrugged off the 2 percent payroll tax increase.
Cigna - Citi is downgrading the health insurer's stock to "neutral" from "buy" on a valuation basis, with shares near an all-time high.
Six Flags Entertainment - Goldman Sachs has initiated coverage of the amusement park operator with a "buy" rating, saying the sector has a lack of supply and Six Flags in particular is still early in the process of growing margins and returns. Competitor Cedar Fair is rated "neutral"; Goldman sees that company further along in its pricing/margin story.
AutoNation - The vehicle retailer reported a 7 percent increase in March new vehicle sales.