Bid credits in simultaneous ascending auctions

I study the impact of bid credits on simultaneous ascending auctions in a model where bidders potentially have complementary values. Although can lead to more equitable distribution items, find an additional unintended consequence: without are exposed winning less desirable set items and will drop out auction sooner when their competitors credits. Calibrating data from Federal Communication Commission's sale licenses 700 MHz guard bands, exposure reduced average non-credited dropout values by 5.7 percent but did not decrease revenues.