收费公路PPP项目最低收入担保机制设计
Minimum revenue guarantee mechanism design for toll road PPP projects

该文研究收费公路政府与社会资本合作（public-private partnerships，PPP）项目中最低收入担保机制的设计原则和方法，以改善收入风险的分担。基于文献综述提出了最低收入担保机制设计的5个原则，建立符合以上原则的随机模型以求解最低收入担保机制的收入下限和上限，利用案例展示了所提出方法的应用，并通过数值模拟验证了该方法的有效性。研究表明：根据目标资本结构来确定最低收入担保水平，有助于大幅减小项目公司的破产风险；根据目标投资回报结合竞标的方式来确定超额收入阈值，从而实现超额收入分享，能有效避免企业通过PPP项目获得超额回报。该方法使得最低收入担保与超额收入分享机制对PPP项目财务状况的改善和为政府带来的或有债务可以测算，能为项目方案评审、财务测算和财政承受能力评估等提供量化依据，并改善政府对PPP项目的支付预算管理。
Abstract：This article describes the principles and methodology used to design the minimum revenue guarantee (MRG) mechanism to improve revenue risk allocation for toll road PPP projects. A literature review shows five critical principles for MRG design which are used in a stochastic model to find the optimal upper and lower revenue thresholds. A case study shows the application and effectiveness of this methodology. This research shows that a minimum revenue threshold determined by the target capital structure significantly reduces the bankruptcy probability of the project company. A maximum revenue threshold jointly determined by a target rate of investment return and a bidding process will prevent the private sector from obtaining excessive profits from the PPP project. These method and models will help with quantitative evaluations of the impacts of an MRG on a PPP project's financial status and the government's contingent liabilities to further improve project evaluations and fiscal sustainability assessments as well as budgeting for PPPs.