The paper compares different auction formats for sale of a single patented innovation for budget constrained bidders. This unit decreases the marginal cost of production in the aftermarket for its owner by an amount which depends on the money invested on the development of this technology. As the bidders have a fixed budget that must be used to pay the final auction price and also to develop the new technology, the winner has incentives to pay a low amount for his unit to increase the amount available to invest in cost reduction. Conversely the loser has incentives to induce induce a higher price to be paid by the winner in order to increase aftermarket profits. This conflict of interest generates the willingness to pay (WTP) for the patent through an endogenous process, which may end up by stablishing a higher WTP for the lowest financed firm. Given this background, the case in which the players have different initial budgets may generate multiple equilibria for all studied auction mechanisms. These equilibria produce di¤erent consumer surplus and, thus, a central government with an unti-trust behavior is able to choose the auction that generates the re�ned equilibrium leading to the highest consumer surplus.