Take a look at some of Thursday's midday movers:
King Digital Entertainment - Shares fell for a second session after its market debut Wednesday. The mobile-game maker was the worst performing IPO this year.
Square 1 Financial - rose 12 percent in its market debut after pricing $5.7 million shares at $18.
TriNet Group - soared 16 percent in its first day of trading after the provider of payroll services offered 15 million shares at $16 a share.
Bitcoin Shop - The Bitcoin-only online retailer fell on reports China's central bank has ordered domestic banks to stop doing business with websites that trade in the digital currency.
GameStop - The seller of video-game products fell after reporting weaker-than-expected fourth-quarter earnings.
Twitter - The social-media company rose after entering a data-sharing partnership with Billboard.
Alcoa - The aluminum maker hit a two-and-a-half-year high after a favorable U.K. ruling that halted the London Metals Exchange's plans to cut industrial metal logjams in warehouses. The ruling was seen as supportive of aluminum prices.
Clovis Oncology - Shares experienced a roller coaster morning after it posted positive findings from a study of its lung-cancer treatment.
Conns - The specialty retailer gained after reporting earnings rose 57 percent in the fourth quarter.
Fred's - The specialty retailer declined after reporting fourth-quarter earnings below estimates.
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—By CNBC's Rich Fisherman.
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