Stock exchange operators compete for order flow by setting "make" fees for limit orders and "take" fees for market orders. When traders quote continuous prices, they can choose prices that perfectly neutralize any fee division, and traders stream to the exchange with the lowest total fee. The...

This paper extends the theory of legal cartels to aliated private value and common value environments, and applies the theory to explain joint bidding patterns in U.S. federal government o.shore oil and gas lease auctions. We show that e.cient collusion is always possible in private value...