供应不稳定时零售商战略库存决策研究

A Retailer's Strategic Inventory Decisions When Supply is Unreliable

针对一个供应商、一个零售商组成的两级供应链系统,研究了存在供应商随机发货和供应商动态定价时的零售商战略库存决策问题,分析了供应商稳定性水平对供应商动态定价、零售商战略库存设置、供应链各方利润的影响。研究表明,零售商为应对不稳定供应所设置的缓冲库存,同时具有抑制供应商定价、提高自身利润的重要作用。最后讨论了零售商设置战略库存的临界条件,即当单位库存持有成本低于某临界值,零售商设置战略库存才是有利的,这对实践中零售商战略库存决策具有参考意义。

The purpose of inventory management is to eliminate high inventory and achieve zero inventory in the supply chain. However, in practice companies often carry some inventory in order to achieve economies of scale in procurement and production, respond to uncertainties, and prevent price fluctuation. Facing the risk of fluctuations in demand, supply chain operations also suffer from all causes of supply uncertainty. In addition, the price of raw materials in the global market is changing rapidly and greatly shortening the cycle of price adjustment by suppliers. As a result, dynamic contract is gradually replacing commitment contract in order to cope with the increasing supply chain uncertainty. Therefore, setting a right inventory level is an effective strategy for the buyer to deal with supply risks and rapid price changes. Supply instability is mainly manifested in two aspects： random yield caused by the uncertainty of production process and supply disruption by unexpected events. One effective way to cope with unstable supply is to set buffer＇ inventory. However, the existing literature focuses on how to set inventory by the buyer to deal with supply instability without considering the impact of inventory setting on the pricing behavior of the supplier. Based on a two-echelon supply chain composed of one supplier and one retailer, this paper adopts the supplier-led Staekelberg dynamic game with unstable supply. At the beginning of every stage, the supplier will announce the wholesale price and the retaiier determines its order quantity and sets inventory according to the supplier＇s pre-set price. The assumption is that the supplier can ensure that the retailer places an order at the first stage, and randomly delivers the order to the retailer at the second stage. This paper focuses on how the retailer can respond to price adjustment and random delivery from the supplier with strategic inventory. This paper analyses how supply stability will influence a retailer＇s strategic inventory, which in return influences its supplier＇s pricing and the profits of all parties in the supply chain. The critical conditions for a retailer to set strategic inventory is discussed and used as practice references for a firm＇s strategic inventory decisions. The research shows that the buffer inventory set by a retailer to fight supply instability can inhibit its supplier ＇ s pricing and increase a retailer＇s profit. In another word, the buffer inventory has strategic significance. The wholesale price in two stages will fall as a retailer increases its strategic inventory. The retailer＇s profit also increases as the strategic inventory increases. However, the strategic inventory should meet the following conditions ： when the unit inventory holding cost is lower than a certain threshold setting up strategic inventory for a retailer is favorable. In addition, the threshold will increase as supply instability becomes worse. This means that as supply instability becomes worse the retailer is willing to hold strategic inventory at a higher cost.