An auction methodology wherein individual demands are bid in lots and an aggregation of several lots is then run as an individual lot to determine if the buyer can attract a lower price offering from bidders by selecting to award the total volume of all of the individual lots to one bidder. A bidder-specific transformation factor for the aggregate lot is computed by combining selected transformed values (one for each lot) that take into account that bidder's price offerings for individual lots and the buyer-specified transformation factors for that bidder. Each bidder is then invited to bid a discount percentage for the aggregate lot. This discount percentage is then used along with the bidder-specific transformation factor to generate that bidder's transformed value for the aggregate lot. The bidder with the lowest transformed value for the aggregate lot may be selected as the winning bidder. The combination of bid transformation and lot aggregation results in obtaining an optimum bid for the buyer because it allows the buyer to accurately evaluate the bids received for the aggregate lot.