Abstract: The server registers a plurality of supplier groups composed of one supplier or a combination of two or more suppliers so as to offer all items constituting a procurement object in a supplier group list. Then, it receives a bid price of a first supplier for an item included in the procurement object from a supplier terminal. Further, it selects the supplier group to which the first supplier belongs to with reference to the supplier group list and calculates a group bid price by summing up the bid prices of the suppliers belonging to the selected supplier group. Finally, it compares the calculated group bid price with the group bid prices of other supplier groups and determines a supplier group to be a candidate for the procurement object.

Abstract: The bid management unit has a lockout management section that determines whether to impose restrictions on submission of bid information by a participant terminal according to a predetermined determination condition, and a lockout timer that control a timing to perform determination in the lockout management section. The bid management unit activates the lockout timer upon occurrence of a predetermined lockout timer start event. Further, the bid management unit imposes restrictions on receipt of bid information from the participant terminal according to the determination in the lockout management section.

Abstract: A control method of reverse auction that is implemented by a server connected to a plurality of supplier terminals through a communication network. The control method first receives bids from the plurality of supplier terminals through the communication network. Then, the server calculates a bid price ratio for relatively comparing bid prices of the received bids. Further, the server determines the distribution of a total procurement amount of a reverse auction target item based on the bid price ratio.

Abstract: A reverse auction method implemented by a server connected to a plurality of buyer terminals and a plurality of supplier terminals through a network. The method selects desired purchase terms as candidates forjoint purchase from desired purchase terms received from the plurality of buyer terminals, and transmits an invitation to participate in joint purchase to a buyer terminal of a buyer corresponding to at least the selected desired purchase terms. Then, the method receives a participation response to the invitation from a buyer terminal of a buyer intending to participate in reverse auction and determining a combination of buyers participating in joint purchase according to the participation response.

Abstract: A method for controlling joint purchase reverse auction. The method first determines a contract price for a total procurement amount putting together purchase desires of a plurality of buyers according to a bid by at least one supplier. Then, it calculates a contract price of each buyer from the contract price for the total procurement amount at least according to a purchase scale of the buyer or a procurement price prior to reverse auction of the buyer.