期权合约下基于CVaR的订单农业供应链协调研究

Coordination of Order-agriculture Supply Chain Based on CVaR under Option Contract

在农产品价格随机波动背景下,以包含一个风险规避型农户和一个风险中性公司的订单农业供应链为研究对象,运用条件风险价值(CVaR)准则研究订单农业供应链最优策略与协调问题。研究结果表明,分散决策情形下的农产品产量和决策双方总收益均低于集中决策情形。对此,在订单农业供应链中引入期权合约,研究发现当农户风险规避程度不很低时,期权合约能够促使农户与公司均实现帕累托改进,并且在期权合约下,农户可通过行权应对农产品价格波动风险,保证农产品产量和自身收益不受风险规避行为的影响;进一步研究表明,当农户风险规避程度较高时,期权合约能够实现订单农业供应链的完美协调。

The order-agriculture has the advantages of reducing the risk of supply chain,promoting the modern agricultural machinery equipment application,improving agricultural production,reducing planting cost,improving farmers’market participation.However,the order-agriculture has many problems in practical application,the low performance rate is especially prominent.Reducing the default rate become the key to the healthy development of agriculture in the future.Option contract is an effective tool to improve the cooperation of supply chain members and avoid the risk of market price fluctuation.Introducing option contract in the order-agriculture supply chain is a powerful measure to improve the performance rate of the supply chain.This paper considers an order-agriculture supply chain with a risk averse farmer and a risk neutral company under the random fluctuation of agricultural product prices.Based on the conditional value at risk(CVaR),we establish Stackelberg game model to study the optimal strategy and coordination of the supply chain.Firstly,we analyze the optimal production quantity decision of the farmer under the decentralized case.Secondly,we analyze the optimal production quantity decision of the order-agriculture supply chain under the centralized case,and compare it with the decentralized decision.Then,the option contract is introduced to analyze the coordination conditions of the order-agricultural supply chain and the pareto improvement range.Finally,the theorems and inferences are verified through numerical analysis.The results show that,the production quantity and total benefits of both parties in the decentralized decision are lower than those in the centralized decision.With the risk aversion of the farmer,the production quantity and the benefit of the whole supply chain both reduce,and the higher the farmer’s risk aversion,the lower the production quantity and benefits of both members.After the introduction of the option contract,when the option execution price is low,the production quantity and the farmer’s benefit reduce with the increase of his risk aversion.When the option execution price is high,the production quantity and the farmer’s benefit have no relationship with his risk aversion.When the farmer’s risk aversion is very low,the option contract cannot achieve pareto improvement,while when the farmer’s risk aversion is not very low,the pareto improvement range makes the benefits of the farmer and the company both higher than those under the decentralized case.Further research shows that the option contract cannot achieve the perfect coordination of the supply chain when the farmer’s risk aversion is not too high,while it can fully coordinate the supply chain when the farmer’s risk aversion is high.Besides,the pareto improvement range and perfect coordination range are both increase with the increase of the farmer’s risk aversion.In real life,farmers should actively buy option contracts from the company to avoid the risk of price fluctuation and improve the agriculture production quantity and benefits.To encourage farmers to buy option contracts,the company should set the option fee and option execution price according to farmers’risk aversion.Specifically,for farmers with low risk aversion,the company can reduce the option fee or increase the option execution appropriately.While for farmers with high risk aversion,the company may promote the option fee or reduce the option execution price.Furthermore,if farmers are with low risk aversion,it does no good to introduce option contract in the supply chain as a coordination mechanism.If farmers are with high risk aversion,the introduction of option contract is beneficial to both the company and farmers,and can achieve the perfect coordination of the supply chain.Nevertheless,this study only considers the uncertainty of the market price of agricultural products and farmers’risk aversion,the uncertainty of the market demand and companies’risk aversion can be further studied.