Good delivery bars that are held within the London bullion market (LBMA) system each have a verifiable chain of custody, beginning with the refiner and assayer, and continuing through storage in LBMA recognized vaults. Bars within the LBMA system can be bought and sold easily. If a bar is removed from the vaults and stored outside of the chain of integrity, for example stored at home or in a private vault, it will have to be re-assayed before it can be returned to the LBMA chain. This process is described under the LBMA's "Good Delivery Rules".