After-hours buzz: TWTR, GLUU, BATS & more

Pedestrians walk past an American flag displayed outside of the New York Stock Exchange (NYSE) in New York.
Michael Nagle | Bloomberg | Getty Images
Pedestrians walk past an American flag displayed outside of the New York Stock Exchange (NYSE) in New York.

Check out the companies making headlines after the bell on Thursday:

Shares of Twitter fell more than 2 percent in after-hours trade Thursday after RBC Capital Markets downgraded the Silicon Valley company amid concerning advertiser survey data. The firm downgraded the social media company to "underperform" with a $14 price target (down from $17).

Glu Mobile, the maker of the mobile game "Kim Kardashian Hollywood," announced a one-year extension through 2020 with Kim Kardashian West's corporation. As a result, Glu may choose to develop additional games featuring the celebrity, in addition to developing updates for its current role-playing game. Shares of the game developer briefly popped in after-hours trade.

Shares of Imperva spiked 15 percent after news that it had become the subject of takeover interest from Cisco and IBM, among others. Bids for the cybersecurity company are reportedly due in about 2 weeks.

Bats Global Markets shares surged more than 24 percent on a Bloomberg report that CBOE Holdings is in talks to buy the firm. A Bats spokesperson on Thursday told CNBC they "do not comment on market rumors or speculation."

--CNBC's Ryan Ruggiero contributed to this report.