Abstract:

The model of emergency material reserved by enterprises is one of the effective approaches for governments to enhance post-disaster supply capability. In order to further improve efficiency of cooperation， research is conducted on the purchase-reserve and subsidy issues of material procurement under the reserve mode， considering subsidizing unused materials to enhance quantity flexibility contracts. After deriving the optimal material reserve strategy for the enterprise， a corresponding supply chain coordination mechanism is designed. Using quantity flexibility contracts as a comparative benchmark， the superiority of subsidy flexibility contracts is proved. Finally， conditions for both the government and the enterprise are also provided to achieve coordinated mutual gains. Specifically， the following conclusions and managerial implications are yielded：（1） Under subsidy flexibility contracts， whether the enterprise chooses to establish a reserve partnership with the government depends not only on the probability of disaster occurrence during the reserve period but also on the procurement price and the level of subsidy offered by the government. If the disaster probability is low， the enterprise will only agree to pre-reserve materials for the government if both the subsidy and procurement price exceed certain thresholds. Conversely， if the disaster probability is high， the enterprise will be inclined to engage in cooperation with the government， regardless of the subsidy level， as long as the procurement price exceeds its critical value. This finding provides a reference for enterprises in deciding whether to participate in cooperation and determining the quantity of material reserves. It also offers theoretical support for governments in setting contract parameters.（2） Although the enterprise may accept the contract for pre-disaster material reserves when the procurement and subsidy prices are favorable， especially when disaster probabilities are low， the government may forgo offering such contracts due to high overall costs. Cooperation based on subsidy flexibility contracts is more likely to emerge when disaster probabilities are high. To enhance the overall cooperation efficiency between the government and the enterprise， the optimal material reserve strategy is explored under centralized decision-making and a supply chain coordination mechanism is proposed. This mechanism is found to be solely dependent on material-related costs and prices， and it is not influenced by the disaster occurrence probability or the specific distribution of post-disaster material demand. This simplifies the design of coordination mechanisms for the government and demonstrates the robustness and practical value of the proposed approach. Since the overall cooperation efficiency remains unchanged with subsidy price， both parties can negotiate this price to balance their interests. A higher subsidy price benefits the government by reducing costs， while a lower price favors the enterprise in terms of profit maximization.（3） On the basis of supply chain coordination， the impacts of factors on both the government and the enterprise are further analyzed. Specifically， as the disaster probability rises and spot market procurement price increases， the cost-benefit outcomes for both parties increase. The government's costs are more sensitive to changes in disaster probability and spot market procurement prices compared to the enterprise’s profits. Additionally， the change of subsidy price can alter the sensitivity of cost-benefit outcomes to these factors. When subsidy prices are low， both parties should closely monitor changes in disaster probability and spot market procurement prices， especially for governments.（4） Comparing subsidy flexibility contracts to quantity flexibility contracts， it is found that the former not only achieves supply chain coordination but also enhances overall cooperation performance by increasing material reserves. By setting reasonable subsidy prices， both the government and the enterprise can achieve win-win cooperation， highlighting the superiority and practical value of contract improvements. As disaster probabilities and spot market procurement prices rise， the advantages of subsidy flexibility contracts become more pronounced. However， this also increases the difficulty of achieving win-win cooperation. Therefore， both parties need to be more cautious in setting subsidy prices under such circumstances.

Key words: emergency material reserve, government-enterprise cooperation, subsidy, contract improvement, supply chain coordination