Abstract: With the market competition getting fiercer, it's difficult to maintain a competitive advantage by just lowering product price. Thus, more and more manufacturers begin to provide related service with the product to improve product value and enhance brand competitiveness. In this context, high level of the service can improve customer satisfaction and increase product sales. However, there always exists uncertain market risk in the manufacturer's operation. Demand uncertainty affects not only the product pricing but also the service decisions, and thus may reduce the overall profits of the supply chain. Therefore, it's necessary to address the problems of information sharing and incentive strategy in the product service supply chain (PSSC) when the manufacturer supplies both the product and the related service under the uncertain demand environment.
This paper includes the following four parts. Firstly, a multistage game model of incomplete information is built to analyze the impacts of the retailer's information sharing level, the manufacturer's service efficiency and the consumer's service sensibility on the equilibrium decisions and the value of service. Secondly, the values of information sharing to the PSSC and supply chain members are explored, and two effects of information sharing are revealed, namely the positive service improvement effect and the negative double marginalization effect. Thirdly, the feasible condition of information sharing is analyzed and a two-part compensation contract is proposed to encourage the retailer to share demand information. Finally, the main conclusions are illustrated through numerical examples.
The result indicates that the demand information sharing by the retailer helps the manufacturer to adjust service level in respond to market fluctuation, and thus effectively enhances the service value of the whole supply chain. However, information sharing is not always beneficial to the PSSC. When the manufacturer's service efficiency or the consumer's service sensitivity is very low, the positive service improvement effect is limited and cannot offset the negative double marginalization effect, therefore the information sharing would result in the loss of supply chain performance. But when the manufacturer's service efficiency or the consumer's service sensitivity is low, the two-part compensation incentive contract can achieve complete information sharing in the PSSC, and the difficulties to implement the contract decrease with the retailer's information accuracy, the manufacturer's service efficiency and the consumer's service sensitivity. In particular, when the manufacturer's service efficiency or the consumer's service sensitivity is high, complete information sharing can improve the retailer's profit and the retailer will share information voluntarily, which creates a "win-win" situation in the supply chain.

Key words: product service supply chain, information sharing, demand forecast, servitization of manufacturing