BBL is an elective cosmetic procedure. As such, it is not covered by insurance. While it is highly unlikely, you could make a case for the medical necessity of liposuction (as a means of debulking). The fat transfer component, on the other hand, would not be covered.As always, discuss your concerns with a board certified plastic surgeon (ABPS).
In my practice I have never had any insurance cover a BBL. If it is for a cosmetic purpose and not reconstructive from an accident/cancer, I highly doubt it would be covered. I wish you luck!