Collusion in Repeated Procurement Auction: a Study of Paving Market in Japan

We present an econometric approach to the problem of detecting bid rigging in procurement auctions using bidding data for paving works in Ibaraki City, Osaka, Japan. We first show that sporadic price wars are caused by the participation of potential goutsiders.h Assuming that the ring is all-inclusive in the absence of these outsiders, we estimate the rule by which the ring selects the winner. It is found that the ring tends to select a bidder whose time elapsed from the last winning is long and whose winning amount in the past is small relative to other bidders.