Hiding information in open auctions

The defining characteristic of an open format is that it allows to aggregate extra information on top of the one that is available ex-ante. This paper shows that bidders may have an incentive to strategically manipulate this extra flow of information by employing jump bids. We show that jump bidding can have a dramatic impact on equilibrium behavior and affect revenues and efficiency in an ambiguous manner. Contrary to the common belief that jump bids are anti-competitive, it may also result in higher revenues and efficiency