Specialty (alternative) credit bureau
The subprime-focused bureaus tribal lenders use instead of Equifax, Experian and TransUnion.
What "specialty (alternative) credit bureau" means
Beyond the three major bureaus sits a set of specialty consumer-reporting agencies built for subprime and short-term lending — chiefly Teletrack and DataX (Equifax), Clarity (Experian) and FactorTrust (TransUnion). Tribal and payday lenders underwrite from these files, which is what "no credit check" really means.
You have the same federal rights to these files as to the majors: one free report a year and the right to dispute errors. Pulling them is worth doing if you are challenging a tribal loan that was reported there.