Microsoft's newly formed internal Halo developer 343 Industries has twittered, through their official Halo Waypoint account, that Gearbox is not hiding a Halo project.
Recently studio boss Randy Pitchford of Gearbox was elusive when asked if they're up to something in the Master Chief universe, but it seems he was just teasing us. What a rascal.
"For the record, Gearbox is NOT working on a Halo title for Microsoft," 343 devs.
A Microsoft representative confirmed the twitter accounts legitimacy to "Halo Waypoint is an official 343 Industries Twitter account," they said. "For the record, we can confirm that Gearbox is not working on a Halo project. We are focusing our efforts on Halo 3: ODST, Halo Legends, and Halo: Reach, as well as our new Xbox Live destination called Halo Waypoint.":
That's that rumour/speculation/Halo chatter dispelled then, at least until someone says, posts, twitters or sneezes something else on the matter.