Acme Packet Inc. (Nasdaq: APKT) shares were up 16.3% to $65.03, on volume of 3.8 million, better than twice its full-day average, after the maker of transmission devices for telecommunications late Tuesday reported fourth-quarter earnings that beat expectations and hiked its 2011 outlook.

Citigroup Inc. (NYSE: C) traded in 99.7 million shares, catching up on its daily average volume of 566 million. Prices for the stock dipped 0.7 percent to $4.87, after seizing control of music’s EMI Group.

JDA Software Group Inc (Nasdaq: JDAS) shares plunged 6 percent to $29.05, on volume of 769,205 shares, or double its daily average, after the maker of software used by retailers late Tuesday forecast 2011 revenue below Wall Street’s expectations.