Definition of Auction ring:
Group of buyers at an auction who collude not to bid against one another in order to keep the auction price low. The items bought at the first (legal) auction are later sold at an illegal private auction (called knock out auction) and the resulting profits are shared among the members of the ring. It is a criminal offense to participate in an auction ring, and the original seller has the right to annul the sale already made to a member of any such scheme.
Meaning of Auction ring & Auction ring Definition