资本结构与盈利能力的关系:我国铁路上市公司实证研究

The Relationship Between Capital Structure and Profitability: Empirical Study on China’s Listed Railway Companies

资本结构对于铁路行业的筹资活动有重要意义。本文旨在考察资本结构与盈利能力的关系,利用主成分分析法、固定效应模型和二次曲线模型检验我国上市铁路企业是否存在优化的资本结构。首先分析我国上市铁路企业资本结构和盈利能力的现状以及其背后的原因,然后运用主成分分析法提取三个主成分因子。在实证部分,基于资本结构的定义,提出三个研究假设,探讨资产负债率和长期负债率如何影响盈利能力。研究结果表明我国上市铁路行业企业的盈利能力与负债率和长期负债率呈显著正相关;当资产负债率达到86.76%时,铁路上市公司的盈利能力可以最大化。这一结论对优化铁路企业的资本结构具有重要意义。

The research aims to examine the relationship between capital structure and profitability and to test for the existence of an optimal capital structure for China’s listed railways industries using principal component analysis, a fixed effect regression model and quadratic regression analysis. Firstly, we analyzed the status quo of the capital structures and profitability of China’s listed railways companies, and the reasons behind this. We then conducted the principal component analysis to extract three principal component factors, namely, profit return, interest return and asset return. Next, the profitability component score was calculated as a proxy for profitability. In the empirical section, we proposed three research hypotheses, based on the definition of capital structure, to explore how debt ratio and long-term debt ratio affect profitability. Lastly, we concluded that the profitability of China’s listed railways companies is significantly and positively correlated with both the debt ratio and the long-term debt ratio. Additionally, it was found that an optimal asset-liability ratio exists and when it reaches 86.76%, the profitability of a company can be maximised. This conclusion is of great significance for the optimisation of the capital structure of railways industries.