Abstract: Emergencies lead to random changes in commodity market prices and market demand, which could entail to the uncertainty of market demand. If the retailers conceal the sales cost information from the suppliers at this time, under such circumstances, the attitudes of suppliers towards risks may change from risk neutral to risk aversion when suppliers face these uncertainties. In this paper, it aims to explore whether the supply chain can still achieve coordination when the node enterprises in the supply chain cooperate with each other by repurchase contract under the condition of stochastic prices, asymmetric information of sales cost and risk aversion of suppliers in this context, and it also intends to find out the constraints that ought to be satisfied by the optimal decision variables of each node enterprise in the supply chain to achieve coordination. First, under the above assumptions, a repurchase contract model is constructed based on stochastic market prices, asymmetric sales cost information and suppliers’ risk aversion. Then, the solution is solved and verified by numerical simulation. After that, the impact of the coupling effect of information asymmetry and risk aversion on the relevant decision variables of the supply chain is analyzed. The results show that the relevant decision variables in the supply chain boom to have bifurcation mutation phenomenon based on stochastic prices as long as the suppliers take risk aversion towards risks no matter whether the information is symmetric or not. Meanwhile, the retailers can get extra revenue when they conceal the private sales cost information no matter whether the commodity market price is random or whether the supplier is risk averse or not, but at the same time, it may do damage to the suppliers and the whole supply chain. Apart from this, the more asymmetric the information in the supply chain is, the greater the oscillation amplitude of relevant decision variables in the bifurcation mutation region will be. And it is concluded that the bifurcation and mutation phenomenon is unique after the coupling effect of market price randomness and participants’ risk aversion, which has nothing to do with the symmetry of information. Retailers can take advantage of information asymmetry to obtain extra benefits, but it will damage the partners (suppliers) and the whole supply chain. It is suggested that the best strategy for the suppliers to deal with the retailers shall be to design a cooperation mechanism to promote the retailers disclose the sales cost information in the lowest cost way. And in addition, it is suggested that suppliers should deal with external risks with a stable mentality (risk neutral), which is more conducive to improve their own decision-making level.

Key words: stochastic market price; asymmetric information; risk aversion; buy-back contract; bifurcation mutation