Auctions have regained interest from researchers due to its differentnew applications (Google AdWords auctions, cloud computing auctions,privacy auctions, and white spaces spectrum auctions). In this work inparticular we explore auctions for spectrum that can be allocatedeither to a Abstract single bidder (for licensed use) or to a collection ofbidders (for unlicensed use). In this auction, a number of individualbidders all try to get the spectrum for their exclusive use and agroup of other bidders try to get the spectrum for their collectiveuse. The objective is to study these auctions and compare theirdifferent properties.