资产泡沫、技术创新与经济增长

本文从理论和实证两个角度研究了资产泡沫发生、技术创新与经济增长之间的相关性。理论方面,本文构建了符合我国经济典型事实的熊彼特经济增长模型。模型中,企业家在为研发筹集资金时面临融资约束。由于融资约束的存在导致资本市场的资金供过于求,发生资产泡沫可促进企业平均的研发投入增加,研发成功的概率相应上升。实证方面,本文采用FF-TVP-SV-VAR和TVAR模型以及我国2000-2016年的月度数据分别对理论分析得出的结论进行检验。实证结果表明,资产泡沫发生可以促进技术创新,但该效应依赖于融资约束。此外,本文识别了融资约束的两个门限值。低于下限值时,资产泡沫可通过技术创新效应促进经济增长;高于下限值时,资产泡沫的技术创新效应较弱,因而对经济增长产生负向作用。

Asset Bubbles,Technological Innovation and Economic Growth

The relationship between asset bubbles, technological innovation and economic growth is investigated from the perspectives of both theoretical modeling and empirical study. The previous literaturesreach the inconsistent conclusions on the impacts of asset bubbles on the economic growth. Technological innovation is normally ignored in the bubble models. However, it is found that innovation plays a key role in shaping the relationship between the asset bubbles and the economic growth. The relationship between the asset bubbles and the economic growth depends on the intensity of financial constraint faced by the firms. When the financial constraint is severer than a high threshold value, there exists a positive influence of asset bubbles on the economic growth, suggesting that the asset bubbles drive the technological innovation; vice versa.When the financial constraint fall between a high and a low threshold value, the relationship between asset bubbles and economic growth is ambiguous.The relationship between the asset bubbles and the economic growth through technological innovation is tested by presenting a list ofthe stylized facts, building a theoretical model and conducting an empirical study. it is found the consistent results which are shown below:First, the dynamic evidences between the asset price and the innovation in China are presented, and find a positive relationship between the two variables is found. Furthermore, it is found that the firms in China face the severe financial constraints, and the intensities of the constraints have become great for last few years. The above stylized facts may raise the question about whether the asset bubbles can boost the economic growth.Theoretically, a Schumpeterian economic growth model where the entrepreneurs face the financial constraint when they finance the R&D. As a consequence, the supply will be greater than demand in the capital market. Assume that the asset bubbles occur in this case, the rising assert price relaxes the financial constraint through mortgage loans, which implies that the entrepreneurs can finance the R&D more easily than ever before. Therefore, the asset bubbles could boost the R&D expenditure and improve the probability of successful R&D. Thus, a positive relation between the asset bubbles and the innovation is found, which is ignored in the previous literatures. The endogenous growth model is combined with the bubbles model by incorporating the technological innovation, which fill the gaps in the currently available studies.Empirically, the FF-TVP-SV-VAR and TVAR models are utilized to examine the relationship between the asset bubbles, the technological innovation and the economic growth by employing the monthly data covering a period from 2000 to 2016. It is found that the asset bubbles can boost the technological innovation subject to the financial constraints. In addition, the two threshold values of financial constraints are identified. Furthermore, the robustness of the baseline results is tested by employing the TVTP-MS-VAR model.This paper has the important policy implications. First, the asset bubbles may be beneficial to the economic growth, depending on the intensity of financial constraint. The government sectors should pay a close attention to the evolution of financial constraints and direct the funds to the R&D sectors. Second, although the asset bubbles can boost the economic growth under a certain situation, the over-bubblization may trigger the systemic risk and is unbeneficial to the economic growth. Thus, the government should monitor the dynamics of bubbles.