http://www.gameinformer.com/b/news/archive/2014/08/05/borderlands-series-tops-18-million-units-sold.aspx

Take-Two may have posted a loss for the first quarter of its current fiscal year, but it exceeded expectations on the strength of its catalog titles. Grand Theft Auto V, NBA 2K15, and Borderlands 2 continue to be strong performers.

2K Games tells Joystiq that the Borderlands series has crossed 18 million titles shipped, with 10 million of those coming from Borderlands 2. Gearbox and 2K Australia are getting ready to release the third major Borderlands game, subtitled The Pre-Sequel, in October.

Take-Two president Karl Slatoff expects big things from the Pre-Sequel despite its release on PC and last-gen consoles only. “We have a lot of faith in the Borderlands franchise,” he said on the earnings call. “There's still a huge install base of consumers; Borderlands is beloved .... We have very high hopes for The Pre-Sequel for current-gen platforms and PC, indeed. But it will be reliant on quality, and we expect to deliver a really high-quality game.”