A long literature in theoretical and empirical economics suggest that collusion can greatly reduce economic efficiency. Economic theory predicts that one of the main challenges a cartel faces is to monitor and enforce cartel agreement. Auctions are highly transparent economic mechanisms. In the PCS C Block, for example, bid amounts, bidder identities and bidder eligibility were publicly observed during the course of the auction. While auctions have many advantages, a potential disadvantage is that this transparency facilitates collusion. We concur with Marshall and Marx (2007) who have argued that collusion is of Örst order important in auction design.