BioShock isn't going away anytime soon, according to Take-Two CEO Strauss Zelnick.

Speaking at the MKM Partners Investor Day conference, Zelnick reiterated that "the franchise is in the hands of 2K," but that "BioShock is unquestionably a permanent franchise for our company and one that we do believe in."

No new entries in the series have been announced; Zelnick says 2K will "make announcements in due time."

Meanwhile, BioShock creator Ken Levine is still at work on an unannounced game for Take-Two.

Little is known about it, but it is a game about "fluid relationships" running on Unreal Engine 4, set in a brand-new sci-fi universe.

Zelnick said in his speech that Levine's game is "something highly creative and innovative."

BioShock Infinite, the most recent game in the BioShock series, has sold over 11 million copies to date.