Package Bidding: Vickrey Vs. Ascending Auctions

The Vickrey and ascending package auctions are found to have identical equilibrium performance in the case where goods are substitutes. In the remaining cases, the Vickrey auction retains its incentive advantages at the cost of setting prices that are so low that the outcome is not in the core of the corresponding exchange economy. The Vickrey auction also introduces biases that distort investments in new technology. By contrast, the ascending package auction has its equilibrium outcomes in the core, provides neutral investment incentives, and is easier for bidders to understand and manage.