It is common for suppliers to underestimate costs in procurement auctions, thereby decreasing the bid price and profit on completion of the supply, and potentially resulting in supply disruptions. We study the bidding decisions of suppliers that underestimate costs when the buyer uses first-price or second-price sealed-bid procurement auctions. We study the effects of underestimating costs on the bid prices and performance decisions under different auction modes and propose renegotiations after procurement auctions to cope with supply disruptions. The results show that: (1) using first-price or second-price auctions, underestimating costs does not guarantee a positive profit on completion of the supply. When the winning supplier's degree of underestimation is high enough, underestimating costs may cause supply disruptions. (2) When the buyer faces supply disruptions, if the expected payment for re-selecting another supplier is not less than a certain threshold value, the buyer can prevent supply disruptions through renegotiations after procurement auctions. (3) Compared to the situation where all suppliers' budgeted costs are accurate, underestimating costs always decreases the supplier's profit. For the buyer, when the supplier completes the supply under the original or renegotiated contract, underestimating costs can decrease the procurement costs. Finally, we show the main conclusions with numerical examples.

中文翻译：

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采购拍卖后重新谈判：应对因低估成本而造成的供应中断

供应商在采购拍卖中低估成本的情况很常见，从而降低了投标价格和供应完成后的利润，并可能导致供应中断。我们研究了当买方使用第一价格或第二价格密封投标采购拍卖时供应商低估成本的投标决策。我们研究了不同拍卖模式下低估成本对投标价格和绩效决策的影响，并建议采购拍卖后重新谈判以应对供应中断。结果表明：（1）使用第一价格或第二价格拍卖，低估成本并不能保证在供应完成时获得正利润。当获胜供应商的低估程度足够高时，低估成本可能会导致供应中断。 （2）当买方面临供应中断时，如果重新选择供应商的预期费用不低于一定阈值，买方可以通过采购拍卖后重新谈判来防止供应中断。 (3)与所有供应商的预算成本都准确的情况相比，低估成本总是会减少供应商的利润。对于买方而言，当供应商根据原合同或重新谈判的合同完成供货时，低估成本可以降低采购成本。最后，我们通过数值例子展示了主要结论。