PPP项目股权结构的优化研究

The determination and optimization of equity structure is one of the critical successful factors for public-private partnerships (PPP) projects, which will facilitate project governance, balance interests and risk-sharing of project stakeholders as well as protect the public interests, etc. To overcome the limitations of past studies, this research focuses on systematic optimization of equity structure of PPP projects, including identifying its key influencing factors, proposing optimization strategies and methods under uncertain environment, multi-objectives and joint-adjustment: 1) to identify comprehensively the optimization objectives and functional definitions of PPP equity structure optimization, and to depict associated key influencing factors as well as the inherent causality between them using data mining method; 2) to analyze the impacts of uncertain risk factors on project revenue using numerical simulation analysis method; to explicit the main incentives and demands of various stakeholders through investigation and interview and to establish a multi-objective optimization model for PPP equity structure under uncertain conditions; 3) to depict the inherent interaction relationship between the equity structure and concession period by theory inference and factor analysis so as to propose their joint-adjustment mechanisms; 4) to establish the decision principles and optimization model of equity structure for PPP projects through multi-agent simulation and then to verify the principles and model by case studies. This research expands and improves the existing researches in particular on research scope and research method. The conclusions could server as reference for PPP project stakeholders during contract negotiation on equity structure and provide guidance for the public during relevant regulations and policy making.

PPP项目股权结构的确定和优化是PPP项目成功的重要保障之一，有利于项目治理、均衡各方利益与风险分担等。本申请将系统研究PPP项目股权结构优化相关问题，分析股权结构的关键影响因素，并提出其在不确定性、多目标冲突、联动调整等复杂环境下的优化策略：1)识别PPP股权结构优化目标与功能定义，结合数据挖掘提炼其关键影响因素及因果关系；2)使用数值模拟分析风险因素对项目收益的影响，通过对项目干系人的调研和访谈明确其利益诉求，构建不确定性条件下PPP项目股权结构的多目标优化模型并求解；3)考虑股权结构与特许期的联动调整，根据理论推导和因素分析揭示其相互作用机理；4)通过多主体模拟仿真验证PPP项目股权结构优化的有关原则、模型和方法。本申请在研究对象、研究方法等方面对现有研究进行了拓展和完善，既可为项目各参与方就PPP项目股权结构的有关谈判提供参考，也可为相关法规和政策的制定提供支持。

股权结构优化是PPP项目融资和项目治理领域关注的核心问题之一。近年来，公共部门通过投入政府资金（股权投资和政府补贴）正日益紧密的参与到PPP项目融资中。在此背景下，结合政府资金对股权结构的影响，研究PPP股权结构在不确定条件、多目标约束和动态博弈等情形下的优化行为，既可拓宽对PPP股权结构优化理论的认识，也可为相关决策提供工具。.本研究首先通过文献调研和理论研究总结了PPP项目的主要资金来源及其特点，分析了主要利益相关方在PPP项目股权结构优化中的诉求。随后，结合现金流量折现法识别了股权结构决策中的关键指标，并对政府补贴支付方式以及债权投资、社会资本股权投资、政府资金等不同资金的折现率进行了分析。在此基础上，提出了PPP项目选择最优股权结构的决策框架和“三阶段”的决策流程，即“提出初步的股权配置方案—>筛选可行的股权配置方案—>综合评价方案及调整优化”，为后续优化模型的建立奠定了基础。.其次，为考虑不确定性因素对PPP项目未来现金流的影响，采用蒙特卡洛模拟对影响PPP项目收益和成本的关键风险因素，包括建设成本、运营成本和客流量等，进行了模拟分析。将蒙特卡洛模拟嵌入到遗传算法适应度函数的计算模块可提高计算速度，保证算法收敛。通过模型在北京地铁四号线数值算例的应用表明：优化后的股权结构优于项目实际的融资安排，公共部门需适当增加财政资金投入以抵消不确定因素对项目收益的不利影响。.再次，针对多目标约束的PPP项目股权结构优化，分别以两个子目标，即社会资本股权投资净现值的最大化与公共部门投入的政府资金现值的最小化，代表社会资本和公共部门各自的利益诉求。采用带精英策略的非支配排序遗传算法对该问题进行求解，得出了一组满足双方利益诉求的帕累托解，从而提升了PPP项目管理的灵活性。随后，将模型在某轨道交通PPP项目中进行了应用，并采用逼近理想解法（TOPSIS）对结果进行了评价。.最后，基于PPP项目的股权结构决策过程中公共部门与社会资本之间的相互博弈，构建了PPP项目股权结构的不完全信息动态博弈模型，求解了PPP项目的最优股权结构和最优特许价格，并以数值模拟方法分析了各关键定量因素变动对PPP项目最优股权结构的影响。