The auctioneer will specify a number of terms of the service, such as frequency, size of vehicle, timing of service, the maximum permitted fare paid by some or all the available seats and/or other specifications related to service and quality. The auctioneer can specify either a net or gross contract. In the latter the operator bids for the full operating costs, and all revenue goes to the authority; with net contracts the operator will be granted all revenue, and will bid only for the necessary difference between fare revenue and that needed to make the desired profit. The use of gross contracts reduces the risk of the operator since they do not need to estimate the ridership and will normally give lower bids since there is a lower risk premium in each bid. This option also makes it easier to create free transfer between operators and modes.