Once a government has decided to award aconcession by auction, it needs to decide what kind ofauction to use. For concessions the standard is afirst-price sealed bid auction in which bidders submitsealed envelopes containing their offer and the highestoffer determines the price. The bidding may occur in one ortwo stages. In two-stage bidding the technical parameters ofthe bids are made comparable in the first stage, and onlythe main offer on the core bid parameter is submitted in thesecond. The main offer may relate to a price, a level ofsubsidy, a payment for net worth, or any other appropriateparameter; the discussion in this Note focuses on price.