The Price Effects of Increased Competition in Auction Markets.

Bidding theory predicts low er selling winning bids (higher buying winning bids) as numbers of bidders incre ase. Alternative versions predict that winning bids fall (rise) with the second order statistic, the maximum order statistic, or 1/N. The authors test these pre dictions using data on underwriters' spreads on tax exempt bonds, offshore oil t racts, and National Forest timber. They estimate winning bids using general vari ables for the product and dummies for 1, 2, . . .11 bidders. In all cases mor e bidders meansignificantly lower (selling) winning bids. The expected maximum order statistic fits better than either the second order statistic or1/N, in te n out of twelve cases. Copyright 1987 by MIT Press.