关键词: 股权激励计划, 多时点双重差分, 全要素生产率, 契约结构

Abstract: The 20th National Congress of the Communist Party of China pointed out that high-quality development is the primary task of comprehensively building a socialist modern country, and focusing on improving the total factor productivity (TFP) is the source of power to achieve high-quality development. In recent years, due to the global spread of COVID-19, the global economic recovery has been weak. With the weakness of China's market economy system, insufficient market inspiration, and poor micro-economic vitality, etc., the enterprises' TFP in China is generally not high, and its growth rate is also declining. Therefore, under the dual pressure of a tightening external environment and internal conditions, how to stimulate the enthusiasm and creativity of various employees in the enterprise, and improve the enterprises' TFP has become an important point for promoting the sustainable and high-quality development of enterprises.
Equity incentives, as an effective means to stimulate the vitality of micro subjects, can improve the efficiency of enterprise resources allocation and promote the improvement of labor productivity. At the same time, equity incentive plays an important role in improving enterprise performance and investment efficiency as well as promoting enterprise innovation, which provides the possibility of promoting the improvement of enterprises' TFP. However, the contract theory points out that a scientifically and reasonably designed contract scheme is an important foundation for ensuring the effectiveness of contract execution, and unreasonable design of equity incentive may have a negative impact on enterprises. Therefore, it is necessary to deeply explore the impact of equity incentive plans and different contract element designs on the total factors of enterprises and their mechanism of action. It is of great significance to optimize the design of equity incentive mechanism of listed companies and achieve high quality development.
This paper takes China's A-share listed companies from 2004 to 2021 as samples. Firstly, we use the multi-time DID to examine the implementation effect of equity incentive plans from the perspective of TFP, and conducts a robustness test in terms of the parallel trend test, excluding other policy interference, propensity score matching, heterogeneity treatment effect test, and placebo test. Secondly, using the intermediary effect model, the paper examines the specific path of equity incentive plans to improve the enterprises' TFP from three aspects: innovation incentive effect, risk taking effect, supervision and governance effect. Finally, based on the perspective of contract structure, this paper further examines the influence mechanism and heterogeneity of different contract factors such as equity incentive intensity, incentive model, incentive object, incentive times and incentive validity period in the enterprises' TFP, and accordingly puts forward countermeasures and suggestions to optimize the design of equity incentive mechanism of listed companies in China.
The results of the study show that: (1)The implementation of the equity incentive plan can significantly improve the enterprises' TFP. (2)The analysis of mechanism based on the intermediary effect model shows that the equity incentive plan mainly improves the enterprises' TFP by promoting corporate innovation, improving enterprise risk taking levels and internal control effectiveness. (3)Based on the perspective of contract structure, a greater intensity of equity incentives, more times of equity incentive implementation, and a longer validity period of incentives all lead to a stronger promotion effect of equity incentives on improving enterprises' TFP. At the same time, compared with core employee equity incentives and stock option models, executive equity incentives and restricted stock models have a stronger improvement in enterprises' TFP. This conclusion is of great significance for the design and realization of high-quality development in the design of the listed company's optimized equity incentive mechanism.

Key words: equity incentive, multi-period DID, total factor productivity, contractual structure