增长期权对最优资本结构的影响研究：企业生命周期的视角

资产构成和生命周期的动态关系决定了企业最优资本结构的变化趋势。本文在利息税盾和破产成本的权衡理论框架下，运用实物期权方法，理论上揭示了增长期权动态执行导致最优资本结构随企业生命周期的变化规律，扩展分析了股东-债权人代理冲突对最优资本结构的影响，并提供了基于中国沪深A股上市公司的经验证据。结果表明：随着企业由年轻走向成熟，增长期权不断执行和在位资产逐渐累积会降低企业总体的破产风险，从而企业最优财务杠杆呈现上升趋势且增长速度逐渐放缓；股东和债权人在增长期权执行决策上的代理冲突导致的投资不足会降低最优财务杠杆，但代理成本随企业生命周期推进呈递减趋势。

Study on the Influence of Growth Options on the Optimal Capital Structure: A Perspective from Firm Lifecycle

The dynamic relation between asset composition and firm lifecycle determines the changing trend of optimal capital structure over time. In a framework with the trade-off between interest tax shield and bankruptcy cost, this paper uses real option approach to demonstrate the evolvement of optimal capital structure over firm lifecycle as a result of the dynamical exercising of growth options, and then extends to analyze the effect of stockholder-bondholder conflict on optimal capital structure, and finally provides evidence from A-share firms listed on Shanghai and Shenzhen exchanges. The results show that the whole bankruptcy risk will decrease as the exercising of growth options and the accumulation of assets-in-place over firm lifecycle, and hence the optimal financial leverage exhibits an increasing trend with decreasing growth rate as the firm gradually becomes mature. In the presence of the agency conflict between shareholders and debtholders on exercising growth options, the appearance of underinvestment will do harm for optimal financial leverage, but the agency cost arising from underinvestment decreases along with firm lifecycle.