Among the stock activity stories for Wednesday, Feb. 20, from The Associated Press:
— Millennial Media Inc.'s shares sank after the mobile advertising company announced an acquisition, reported disappointing quarterly revenue and issued a weak revenue forecast.
— Shares of NetSpend rose to a 2-year high after the debit card provider agreed to be purchased by Total Systems Services Inc. for about $1.4 billion.
— CF Industries' stock dropped after the fertilizer company reported a decline in fourth-quarter revenue that was deeper than analysts had predicted.
— Shares of Chelsea Therapeutics International Ltd. more than doubled in value after the company said the Food and Drug Administration took a more favorable view of a recent study of its drug Northera.
— Shares of Threshold Pharmaceuticals Inc. rose after a Piper Jaffray analyst upgraded the stock as the company prepares to report more clinical trial data for an experimental cancer drug.
— Shares of Texas Roadhouse Inc. rose as the restaurant chain's fourth-quarter earnings beat Wall Street's expectations.