The research was intended to evaluate which were the determinative factors in the price variation of the products bought through electronic reverse auction bidding in the UFV ( Universidade Federal de Viçosa ). To reach the aims, the relation of the price variation and the following variables were tested: number of suppliers, specificity of the assets, transaction frequency, amount purchased, opportunism of the agents, time of existence and invoicing of the winner company, and the bids amount in the dispute. Pearson Correlation and Multiple Linear Regression were carried through with the intention to explore the relations between the variables and to construct a model to measure the prices variation. The results demonstrated that the number of suppliers, the specificity of the assets, the bought amount and the frequency of the transactions had a combined explanation influence on 67.4% of the variations of the prices practiced in biddings. As a result, the public agencies must develop actions that search to maximize the effect of these variables in the dispute, in order to obtain, in this way, greater economic profits through the reduction of the prices paid in their bidding processes.
electronic bidding; public purchases; auctions theory
