Mixed Ownership Reform and Environmental Sustainable Development—Based on the Perspective of Carbon Performance

Abstract

Mixed ownership reform has contributed greatly to China’s economic development; however, there is little literature on how mixed ownership reform affects carbon performance in the context of environmentally sustainable development. Therefore, this paper takes A-share industrial state-owned enterprises in Shanghai and Shenzhen from 2008 to 2020 as research samples to investigate the impact of mixed ownership reform on carbon performance through empirical tests. The results show that the mixed ownership reform of state-owned enterprises can improve the carbon performance of enterprises. The intermediary test shows that green innovation plays an intermediary role in the relationship between mixed ownership reform and carbon performance. Furthermore, compared with green management innovation, mixed ownership reform has a stronger promoting effect on green technology innovation, and green technology innovation has a greater impact on carbon performance. Heterogeneity analysis shows that in heavily polluted industries and competitive industries, mixed ownership reform of state-owned enterprises has a more significant role in improving carbon performance. Therefore, the mixed ownership reform of state-owned enterprises is of great significance for promoting environmental sustainable development. Overall, this study provides empirical evidence for the environmental sustainable development of state-owned enterprises in emerging markets.

1. Introduction

The Ministry of Ecology and Environment recently announced that air quality across the country was stable and improving in 2022. However, it was worth noting that China’s environmental monitoring data in 2022 also reflect some problems that need to be improved. The ozone concentration in the country and key regions has increased year on year. The turning point of ecological and environmental quality change from quantity to quality has not yet arrived, and the task of ecological and environmental protection remains arduous [1]. In just a few decades, China has completed the industrialization process that took Western developed countries hundreds of years, creating a miracle of rapid economic development and long-term social stability. While making remarkable achievements in economic development, the rough development mode has produced serious environmental pollution and carbon dioxide emissions [2,3], caused huge pressure on the ecological environment [4,5], and posed a great threat to human health [6,7], which has become a challenge to the sustainable development of human society [8]. In order to alleviate environmental pollution and promote public health, the Party’s 20 National Congress has put forward higher requirements for environmental sustainable development [9]. As the main source of environmental pollution, industrial enterprises should actively fulfill their environmental responsibility to help sustainable environmental development [10]. The report of the 20th National Congress of the Communist Party of China also proposed to actively and steadily promote carbon peak carbon neutrality. Moreover, the carbon performance indicator reflects the balance between economic development and environmental protection; namely, the results of environmental governance under economic benefits. Therefore, studying environmental sustainable development from the perspective of carbon performance has important practical significance.

As an important material and political foundation for socialism with Chinese characteristics, state-owned enterprises (soes) are a key force in achieving environmentally sustainable development, and mixed ownership reform is an important measure to stimulate their market vitality. Mixed ownership reform refers to a system that changes the dominance of soes by introducing non-state capital into soes. Studies have shown that mixed ownership reform is quite effective for the economic development of enterprises. Participation of non-state-owned shareholders in governance can effectively reduce the opportunistic behavior of managers, promote the development of innovation activities of state-owned enterprises [11], reduce the agency cost between shareholders and managers, alleviate the underinvestment of enterprises, improve the investment efficiency [12,13], and positively drive the financial performance of enterprises. It can also improve the performance of M&A [14]. However, it is worth noting that the existing literature overlooks the research on mixed ownership reform at the environmental level, and scholars only use the PSM-DID method to discuss the carbon emission reduction effect of mixed ownership reform of state-owned enterprises. Therefore, it is of great significance to explore the impact of mixed ownership reform on environmental sustainable development from the perspective of carbon performance.

By introducing non-state-owned shareholders to participate in governance, the mixed ownership reform increases the right to speak of the directors appointed by non-state-owned shareholders [15] and effectively improves the level of green innovation of enterprises [16]. In addition, mixed ownership reform plays a governance role in the green transformation of state-owned enterprises by optimizing the reasonable allocation of environmental protection subsidies and promoting the active fulfillment of social responsibilities [17]. At the same time, green innovation is the main driving force to realizing the low-carbon transformation of polluting enterprises and promoting sustainable development. Porter’s hypothesis also supports that green innovation compensation can offset compliance costs and achieve the win–win goal of the enterprise environment and the economy [18]. Green innovation not only has a significant positive impact on carbon emission performance [19] but also has a long-term improvement effect on carbon performance [20]. Existing studies have laid a theoretical foundation for exploring the mechanism of green innovation between mixed ownership reform and carbon performance. Therefore, this paper preliminarily raises the following questions: Can mixed-ownership reform improve enterprise carbon performance? Does green innovation play a mediating role in the relationship between mixed ownership reform and carbon performance? Is the relationship between mixed ownership reform and carbon performance heterogeneous in enterprises with different industry characteristics?

In order to fill in the research gaps mentioned above, this paper selected A-share (RMB common stock) industrial state-owned enterprises from 2008 to 2020 as research samples to explore the impact of mixed ownership reform on the carbon performance of enterprises, and on this basis, analyzed the impact mechanism of mixed ownership reform on carbon performance. At the same time, the relationship between mixed ownership reform and the carbon performance of soes may be different in industries with different pollution levels and competition levels. Therefore, this paper attempts to explore the relationship between mixed ownership reform and carbon performance from the perspectives of the heterogeneity of two industries, pollution levels, and competition levels. This study provides empirical support for the impact of mixed ownership reform on carbon performance, clarifies the path for mixed ownership reform to improve carbon performance, and provides a reference for enterprises in industries with different pollution levels and competition levels to play the role of mixed ownership reform in improving carbon performance, so as to achieve environmental sustainable development and make modest contributions to human health.

Compared with the previous literature, the marginal contribution of this paper is mainly reflected in the following three aspects. First, it enriches the research on the economic consequences of mixed ownership reform. The existing literature explores the economic consequences of mixed ownership reform from the perspective of financial performance, innovation level, investment efficiency, and governance efficiency, while few studies focus on the impact of mixed ownership reform on environmental performance. This paper explores the environmental governance consequences of mixed ownership reform from the perspective of carbon performance, which reflects the comprehensive quality of the environment. It is found that the mixed ownership reform significantly improves the carbon performance of enterprises. Second, it enriches the research on the influencing factors of carbon performance. Different from the previous research on carbon performance, mainly through internal factors such as the use efficiency of traditional energy [21], characteristics of the board of directors [22], quality of environmental information disclosure [23], carbon risk awareness [24], and external factors such as government regulation [25] and economic stakeholders [26], this paper studies carbon performance through the system of mixed ownership reform. It deepens the understanding of environmental governance in the process of mixed ownership reform of soes. Third, the paper analyzes the mechanism of green innovation in the process of the influence of mixed ownership reform on carbon performance, and further divides green innovation into two dimensions: green technology innovation and green management innovation, and compares the differences in different types of green innovation in the relationship between mixed ownership reform and carbon performance in a more systematic and comprehensive way. Fourth, the impact of mixed ownership reform on the carbon performance of enterprises is discussed from the two aspects of industrial pollution degree and competition degree, which makes up for the neglect of the heterogeneity of samples in the study on the effect of mixed ownership reform.

2. Theoretical Analysis and Hypothesis Presentation

2.1. Mixed Ownership Reform and Green Innovation

Mixed ownership reform promotes green innovation by playing the “governance effect”. Mixed ownership reform has effectively improved the internal governance of enterprises by introducing non-state capital, improving executive compensation incentives, enhancing the governance level of the board of directors, and forming an equity structure with checks and balances. On the one hand, senior executives are the main decision-makers in corporate behavior activities. The ultimate green innovation efficiency of an enterprise depends on its internal strategic decision-making level and operation and management ability. Executive compensation incentives, as a governance mechanism to coordinate the interests of the executive team and shareholders, can reduce agency costs, effectively alleviate the principal–agent problem, improve the management ability of management, and thus improve the efficiency of corporate green innovation. At the same time, appropriate executive incentives can avoid short-sighted and opportunistic behaviors of management [27], eliminate the negative emotions caused by the poor performance of executives, and encourage the management to make decisions with the goal of maintaining the sustainable development of the enterprise [28] so as to increase the investment in the green innovation of the enterprise. Under the influence of salary incentives, executives can not only make investment decisions for sustainable development to achieve performance goals but can also break the lock state of original low-end technology through green innovation and reform to improve core market competitiveness. On the other hand, mixed ownership reform effectively increases the stability of the board of directors, improves the governance level of the board of directors, and clarifies the responsibilities of the board of directors by introducing the counterbalance equity structure formed by non-state capital [29]. Board governance is the governance behavior of the board of directors for the development strategy and executive decision of the company. The level of governance of the board of directors directly affects the decision-making and behavior of enterprises and then affects the corporate performance and shareholders’ interests. As the focus of strategic decision-making, green innovation is naturally closely related to board governance. At the same time, board governance is helpful to improve enterprise green innovation input [30]. Effective board governance can not only plan the green development direction of enterprises from the governance level and formulate green development strategies and other important matters but also effectively supervise the behaviors of senior executives and encourage them to actively participate in green innovation activities that are beneficial to “win-win” financial performance and environmental performance. Further, the improvement of board governance means that board members have a high degree of interaction [31] and sufficient information exchange, which strengthens the consensus and confidence of enterprises to carry out green transformation.

Mixed ownership reform promotes green innovation by exerting a “resource effect”. First, mixed ownership reform weakens soes’ political goals and social responsibility by introducing non-state shareholders, strengthens soes’ economic goal-driving, and provides environmental support for enterprises’ green innovation. Secondly, mixed ownership reform realizes the effective integration of heterogeneous resources by introducing non-state capital, alleviates the internal financing constraints of enterprises, and provides a sufficient material basis for enterprises’ green innovation. In addition, the integration of different equity rights is conducive to giving play to the advantages of various types of ownership capital and providing external high-quality knowledge and information advantages that are crucial to the green innovation ability of enterprises. Novel and diverse knowledge combinations can significantly promote the formation of high-quality patents [32]. The recombination of external knowledge and internal technology reserve can effectively improve the capability of green technology research and development. The higher risk-bearing capacity of state-owned enterprises and the quality information of non-state-owned shareholders will form a synergistic effect and promote the improvement of the green innovation level of state-owned enterprises [33].

2.2. Green Innovation and Carbon Performance

Green innovation is a whole-process innovation activity carried out in accordance with ecological principles and the development law of the ecological economy. It is an innovation process to improve input–output efficiency and bring economic and environmental benefits to society by transforming products, processes, and management systems, developing new technologies, new ideas, and new policies in order to reduce excessive consumption of resources and energy and environmental pollution. Guided by environmental issues and ecological civilization construction, green innovation focuses on the use of energy-saving production lines to produce green and environmentally friendly products in all links of design and research and development, and adopts end-pollution treatment technology in the process of pollutant discharge, so as to minimize the negative impact on the environment and reduce the carbon emission of enterprises in the whole process from production and research and development to end-pollution treatment [34]. Green innovation promotes economic performance on the basis of effectively improving the environmental performance of enterprises. On the basis of improving organizational efficiency, reducing costs, and meeting the needs of environmentally sensitive consumers, green innovation establishes the green image of enterprises, improves the reputation of enterprises, forms the competitiveness of sustainable development, and effectively improves the economic performance of enterprises. Carbon performance is an indicator integrating economic performance and environmental performance. Therefore, this paper believes that green innovation can improve enterprise carbon performance.

Based on the above analysis, this paper proposes the following hypotheses:

H1. 

Mixed ownership reform is conducive to improving the carbon performance of enterprises.

H2. 

Green innovation plays an intermediary role in the relationship between mixed ownership reform and carbon performance.

3. Research Design

3.1. Data and Sampling

Considering that soes completed the reform of the non-tradable share structure at the end of 2007, this paper selected A-share industrial state-owned enterprises in Shanghai and Shenzhen from 2008 to 2020 as the research sample. The data used in this paper are from the Guotai ‘an database and the website of the State Intellectual Property Office. In order to reduce the influence of other factors on the regression results, the following processing is carried out on the initial sample data based on the existing practices: (1) delete the observed values of ST or *ST; (2) eliminate observations with missing data and outliers; (3) samples of listed companies listed less than one year were deleted, and 6858 observed samples were finally obtained. In this paper, Stata15.0 software was used to process the data. In order to reduce the impact of extreme values on the regression results, the tail reduction of continuous variables was carried out at the level of 1 and 99%.

3.2. Definitions of Variables

3.2.1. Explained Variable

Carbon performance (cp). Carbon performance refers to the economic benefit of carbon dioxide emission per unit of an enterprise. Based on the practice [35], this paper takes the operating revenue generated per unit of carbon emission as the proxy variable of carbon performance. The specific calculation process is as follows: (1) the original data of each energy consumption is converted into tons of standard coal by the conversion coal coefficient; (2) industrial carbon emissions = energy emissions × carbon emission coefficient; (3) enterprise carbon emissions = enterprise operating costs/industry business costs × industry carbon emissions; (4) corporate carbon performance = Ln (corporate operating revenue/corporate carbon emissions).

3.2.2. Explanatory Variable

Referring to the research of Yang et al. (2016) [36], this paper mainly measures the mixed ownership reform of state-owned enterprises from the dual perspectives of “form” and “quality”. Mixdummy is taken as the “form” of mixed ownership reform. Mixdummy takes a 10% shareholding ratio of non-state-owned shareholders as the node. If the shareholding ratio of non-state-owned shareholders in the top ten shareholders exceeds 10%, the enterprise is considered to have a mixed shareholding structure. Otherwise, this paper argues that there is no mixed ownership structure in enterprises. The “quality” of mixed ownership reform is represented by the equity integration degree (mixrate), which refers to the ratio of the smaller to the larger among the shareholding ratio of state-owned shareholders and non-state-owned shareholders. The greater the equity integration degree, the higher the integration degree of state-owned capital and non-state-owned capital, the stronger the check and balance effect, and the better the quality of mixed ownership reform.

3.2.3. Intermediary Variable

Green Innovation (lngi). Referring to the studies of Wang and Wang (2021) [37], the number of green patent applications of enterprises is selected to measure green innovation. The specific calculation process is as follows: sum the number of green invention patent applications and green utility model patent applications and then add 1 to the total number and take the logarithm.

3.2.4. Control Variable

This paper refers to the studies of Zhou et al. (2019) [24], Zhang and Cai (2022) [25] to control the following factors that may affect carbon performance. (1) Corporate characteristics: corporate size (size), asset–liability ratio (lev), return on equity (roe), corporate growth (growth); (2) governance ability: board size (boardsize), proportion of independent directors (indep), management shareholding ratio (mngmhldn), concurrent roles of general manager and CEO (dual) and equity balance (sharesbalance). At the same time, the fixed effect control of different macro factors of region and year was carried out.

Table 1. Variable Definition.

	Definition
cp	Refer to Yan et al. (2019) [35]
mixdummy	If the shareholding ratio of non-state shareholders in the top ten shareholders exceeds 10%, 1 will be taken, otherwise 0 will be taken
mixrate	The ratio between the smaller and the larger of the shareholding ratio of state-owned shareholders and non-state shareholders
lngi	Take the natural logarithm after adding 1 to the number of green patents
size	Natural logarithm of total assets at the end of the period
lev	Ratio of total liabilities to total assets
roa	Ratio of net profit after tax to total assets
growth	(Current operating income–previous operating income)/current operating income
profit	Ratio of net profit to operating income
boardsize	Number of directors
indep	Proportion of independent directors in the number of directors
mngmhldn	Proportion of shares held by management in total issued shares
sharesbalance	Ratio of shareholding ratio of the 2nd–5th shareholder to that of the largest shareholder
dual	If there is a combination of two positions, it will be recorded as 1, otherwise it will be recorded as 0
Region	Virtual variables generated according to the region of the enterprise
Year	Virtual variable generated by year

shows the definition of the main variables.

3.3. Model Setting

To test the relationship between mixed ownership reform and carbon performance, Equation (1) is set up in this paper. If the coefficient ${\mathsf{\alpha }}_1$ in Equation (1) is significantly positive, then hypothesis H1 is verified, indicating that mixed ownership reform can effectively improve carbon performance. In order to test the mediating effect of green innovation, the three-step equation was set up by referring to Wen and Ye (2004) [38]. The first step is to test Equation (2). If the coefficient ${\mathsf{\alpha }}_1$ of the agent variable of mixed ownership reform is significant, the subsequent test will be carried out; if not, the test will be terminated. In the second step, Equation (3) is tested to verify whether there is a mediation effect. If the coefficient ${\mathsf{\beta }}_1$ is significant, it indicates that there is a mediation effect. Otherwise, it does not exist. Thirdly, Equation (4) is tested to verify the mediating role of green innovation. If the coefficient ${\mathsf{\gamma }}_1$ and ${\mathsf{\gamma }}_2$ are significant simultaneities, it indicates that green innovation plays a partial mediating role. If the coefficient ${\mathsf{\gamma }}_1$ is not significant but ${\mathsf{\gamma }}_2$ is significant, it indicates that green innovation plays a complete mediating role. Mix in the above model is the measurement index of mixed ownership reform. mixdummy and mixrate are used to replace Mix in the actual operation.

$${\mathrm{C}\mathrm{P}}_{\mathrm{i},\mathrm{t}}={\mathsf{\alpha }}_0+{\mathsf{\alpha }}_1\times {\mathrm{M}\mathrm{i}\mathrm{x}}_{\mathrm{i},\mathrm{t}}+{\mathsf{\alpha }}_2\times \mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{l}+{\mathsf{\epsilon }}_{\mathrm{i},\mathrm{t}}$$

(1)

$${\mathrm{C}\mathrm{P}}_{\mathrm{i},\mathrm{t}}={\mathsf{\alpha }}_0+{\mathsf{\alpha }}_1\times {\mathrm{M}\mathrm{i}\mathrm{x}}_{\mathrm{i},\mathrm{t}}+{\mathsf{\alpha }}_2\times \mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{l}+{\mathsf{\epsilon }}_{\mathrm{i},\mathrm{t}}$$

(2)

$${\mathrm{M}\mathrm{i}\mathrm{x}}_{\mathrm{i},\mathrm{t}}={\mathsf{\beta }}_0+{\mathsf{\beta }}_1\times {\mathrm{G}\mathrm{I}}_{\mathrm{i},\mathrm{t}}+{\mathsf{\beta }}_2\times \mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{l}+{\mathsf{\epsilon }}_{\mathrm{i},\mathrm{t}}$$

(3)

$${\mathrm{C}\mathrm{P}}_{\mathrm{i},\mathrm{t}}={\mathsf{\gamma }}_0+{\mathsf{\gamma }}_1\times {\mathrm{M}\mathrm{i}\mathrm{x}}_{\mathrm{i},\mathrm{t}}+{\mathsf{\gamma }}_2\times {\mathrm{G}\mathrm{I}}_{\mathrm{i},\mathrm{t}}{+\mathsf{\gamma }}_3\times \mathrm{C}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{l}+{\mathsf{\epsilon }}_{\mathrm{i},\mathrm{t}}$$

(4)

4. Results and Discussion

4.1. Descriptive Statistics

Table 2. Descriptive statistics.

	Mean	Sd	Min	P10	P50	P90	Max
cp	8.6457	2.2375	4.3965	5.6242	8.6819	11.811	12.668
mixdummy	0.4071	0.4913	0.0000	0.0000	0.0000	1.0000	1.0000
mixrate	0.2602	0.2554	0.0018	0.0356	0.1556	0.6926	0.9712
lngi	0.4747	0.9181	00000	00000	00000	1.7918	4.1431
size	22.677	1.3971	20.111	20.974	22.501	24.599	26.483
lev	0.4980	0.1969	0.0815	0.2252	0.5091	0.7410	0.9441
roa	0.0331	0.0570	−0.1653	−0.0161	0.0279	0.09953	0.2120
growth	0.1291	0.3446	−0.4564	−0.1726	0.0816	0.4191	2.2531
profit	0.0495	0.1215	−0.5284	−0.0297	0.04346	0.1697	0.4274
boardsize	9.3529	1.9462	2.0000	7.0000	9.0000	11.0000	18.0000
indep	36.874	5.5780	0.0000	33.3300	33.3300	42.8600	80.0000
mngmhldn	0.4871	2.1470	0.0000	0.0000	0.0006	0.3463	15.203
dual	0.0892	0.2851	0.0000	0.0000	0.0000	0.0000	1.0000
sharesbalance	0.5078	0.4923	0.0179	0.0611	0.3328	1.1982	2.2309

shows the descriptive statistical results of the main variables. It can be seen from Table 2 that the 50-point value of the mixed ownership structure is 0, indicating that more than half of soes do not have a mixed ownership structure, and non-state-owned shareholders have not yet occupied the “right of discourse” in the enterprise. The mean value of the equity integration degree is 0.2602, the minimum value is 0.0018, the maximum value is 0.9712, and the standard deviation is 0.2602, indicating that there is a great difference in the integration degree of state-owned capital and non-state-owned capital, and the mixed ownership reform effect of some enterprises is poor. The mean value of carbon performance is 8.6457, the standard deviation is 2.2375, the minimum value is 4.3965, and the maximum value is 12.668, indicating that enterprises have different levels of carbon performance, which provides data support for empirical research. The descriptive results of the selected control variables are basically consistent with the existing studies.

4.2. Carbon Performance in Different Regions

Figure 1 shows the average carbon performance of provinces where Shanghai and Shenzhen A-share industrial soes are located from 2008 to 2020. As can be seen from the figure, there are great differences in carbon performance in different regions of eastern, central, and western China. The average carbon performance of enterprises in the eastern region is significantly higher than that in the other two regions, and the average carbon performance of enterprises in the western region is significantly lower than that in the other two regions.

4.3. Analysis of Multiple Regression Results

4.3.1. Baseline Regression

Equation (1) is used to explore the relationship between mixed ownership reform and enterprise carbon performance, and the results are shown in

Table 3. Baseline regression.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixdummy	0.539 ***	0.335 ***
	(9.87)	(5.86)
mixrate			1.022 ***	0.559 ***
			(9.72)	(4.82)
Constant	8.426 ***	10.967 ***	8.380 ***	10.741 ***
	(241.82)	(23.48)	(218.71)	(23.03)
Controls	NO	YES	NO	YES
Year FE	NO	YES	NO	YES
Region FE	NO	YES	NO	YES
Observations	6858	6858	6858	6858
R-squared	0.014	0.160	0.014	0.158
F test	0	0	0	0
r2_a	0.0139	0.157	0.0135	0.155
F	97.46	54.10	94.56	53.55

Note: *** represent the significance levels of 1%.

. Columns 1 and 2 are the regression results of the mixed ownership structure and carbon performance. The third and fourth columns are the regression results of equity integration degree and corporate carbon performance. As can be seen from columns 2 and 4 of Table 3, after controlling other factors, the coefficients of mixed ownership structure, equity integration degree, and carbon performance are 0.335 and 0.559, respectively, and are all significant at the 1% level. Hypothesis H1 is verified, indicating that mixed ownership reform is conducive to promoting enterprise carbon performance. From the economic perspective, compared with enterprises without a mixed equity structure, the carbon performance of enterprises with a mixed equity structure increases by 0.335 units on average. When the equity integration degree increases by 1 unit, the carbon performance of enterprises will increase by 0.559 units on average. Specifically, the coefficient of the mixed ownership structure is smaller than the coefficient of equity integration degree, which indicates that compared with the “form” of mixed ownership reform, the “quality” of mixed ownership reform has a more significant role in improving carbon performance. This result is intended to indicate that in the process of promoting ecological civilization construction and supporting the “dual carbon” goal, soes should not only introduce a mixed equity structure to achieve the “form” of mixed ownership reform, but also ensure the “discourse power” of non-state-owned shareholders, achieve mutual checks and balances among heterogeneous shareholders, and improve the “quality” of mixed ownership reform.

4.3.2. Test Results of the Intermediary Effect of Green Innovation

Table 4. Mechanism Analysis.

Variables	(1)	(2)	(3)	(4)	(5)	(6)
	cp	lngi	cp	cp	lngi	cp
mixdummy	0.335 ***	0.074 ***	0.298 ***
	(5.86)	(2.99)	(5.33)
mixrate				0.559 ***	0.256 ***	0.433 ***
				(4.82)	(5.08)	(3.81)
lngi			0.494 ***			0.493 ***
			(18.19)			(18.11)
Constant	10.967 ***	−4.849 ***	13.363 ***	10.741 ***	−4.909 ***	13.162 ***
	(23.48)	(−23.87)	(28.15)	(23.03)	(−24.24)	(27.72)
Controls	YES	YES	YES	YES	YES	YES
Year FE	YES	YES	YES	YES	YES	YES
Region FE	YES	YES	YES	YES	YES	YES
Observations	6858	6858	6858	6858	6858	6858
R-squared	0.160	0.119	0.199	0.158	0.121	0.197
F test	0	0	0	0	0	0
r2_a	0.157	0.116	0.196	0.155	0.118	0.194
F	54.10	38.58	67.68	53.55	39.37	66.99

Note: *** represent the significance levels of 1%.

shows the mediating effect test results of green innovation. Columns 2 and 5 of Table 4 are the effects of mixed ownership reform on green innovation. According to the results, the regression coefficients of mixed ownership reform, whether measured by mixed ownership structure or equity integration, are significantly positive, and are 0.074 and 0.256, respectively, indicating that mixed ownership reform has significantly improved the level of green innovation of enterprises. In addition, compared with the mixed ownership structure, equity integration has a stronger effect on the improvement of green innovation level. The possible reason is that good equity checks and balances are conducive to the internal governance and resource integration of enterprises, so as to improve the green innovation level of enterprises to a greater extent. It can be seen from columns 3 and 6 of Table 4 that, after controlling the influence of green innovation, both the coefficient of mixed ownership reform measured by mixed ownership structure or equity integration degree and the coefficient of green innovation are significantly positive, indicating that green innovation plays a partial mediating role in the relationship between mixed ownership reform and carbon performance, verifying hypothesis H2. In conclusion, compared with the “form” of mixed ownership reform achieved by simply introducing a mixed ownership structure, enterprises should focus on improving the “quality” of mixed ownership reform in the process of promoting mixed ownership. The research results provide a reference path for state-owned enterprises to improve their carbon performance on the basis of promoting corporate green transformation.

4.4. Robustness Test

4.4.1. Change the Measurement Method of Explanatory Variables

In order to ensure the robustness of the regression results, the mixratio of non-state-owned shareholders (the sum of non-state-owned shareholders’ shares in the top ten shareholders) and the mixdegree of non-state-owned shareholders (the proportion of non-state-owned shareholders’ shares in the total shares in the top ten shareholders) are selected to measure the mixed ownership reform [39]. The regression results after changing the measurement method of explanatory variables are shown in

Table 5. Change the measurement method of explanatory variables.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixratio	2.004 ***	1.079 ***
	(9.15)	(4.66)
mixdegree			1.374 ***	0.775 ***
			(10.43)	(5.58)
Constant	8.401 ***	10.899 ***	8.349 ***	10.624 ***
	(221.38)	(23.34)	(213.49)	(22.75)
Controls	NO	YES	NO	YES
Year FE	NO	YES	NO	YES
Region FE	NO	YES	NO	YES
Observations	6858	6858	6858	6858
R-squared	0.012	0.158	0.016	0.159
F test	0	0	0	0
r2_a	0.0119	0.155	0.0155	0.156
F	83.65	53.48	108.9	53.94

Note: *** represent the significance levels of 1%.

. It can be seen from the table that, after controlling the influence of other factors, both the shareholding ratio of non-state-owned shareholders and the participation degree of non-state-owned shareholders are significantly positively correlated with carbon performance, which is consistent with hypothesis H1, proving the robustness of the research results.

4.4.2. Change the Measurement Method of Intermediary Variables

In order to ensure the robustness of regression results, this paper adopts the actual acquisition number (lngi_acquire) after green patent application to measure green innovation. The number of green patents obtained can better reflect the real level of green innovation of enterprises than the number of green patent applications. The regression results after replacing the intermediary variables are shown in

Table 6. Change the measurement method of intermediary variables.

Variables	(1)	(2)	(3)	(4)	(5)	(6)
	cp	lngi_acquire	cp	cp	lngi_acquire	cp
mixdummy	0.335 ***	0.087 ***	0.298 ***
	(5.86)	(4.11)	(5.33)
lngi_acquire			0.494 ***			0.493 ***
			(18.19)			(18.11)
mixrate				0.559 ***	0.221 ***	0.433 ***
				(4.82)	(5.12)	(3.81)
Constant	10.967 ***	−4.303 ***	13.363 ***	10.741 ***	−4.368 ***	13.162 ***
	(23.48)	(−24.75)	(28.15)	(23.03)	(−25.19)	(27.72)
Controls	YES	YES	YES	YES	YES	YES
Year FE	YES	YES	YES	YES	YES	YES
Region FE	YES	YES	YES	YES	YES	YES
Observations	6858	6858	6858	6858	6858	6858
R-squared	0.160	0.128	0.199	0.158	0.129	0.197
F test	0	0	0	0	0	0
r2_a	0.157	0.125	0.196	0.155	0.126	0.194
F	54.10	41.72	67.68	53.55	42.16	66.99

Note: *** represent the significance levels of 1%.

. As can be seen from the second and fifth columns of the table, the coefficients of the mixed ownership structure and equity integration degree are significantly positive, indicating that mixed ownership reform is conducive to improving the level of green innovation of enterprises. It can be seen from columns 3 and 6 of the table that the mixed equity structure, equity integration degree, and coefficient of green innovation are significantly positive, indicating that green innovation plays a partial mediating role in the relationship between the two, which is consistent with hypothesis H2 and proves the robustness of the research results.

4.4.3. Test Results of the Replacement Regression Model

In order to avoid the influence of model selection on the research conclusion, and considering that both carbon performance data and green patent data are positive, a negative binomial model is adopted for regression. The regression results are shown in

Table 7. Test results of the replacement regression model.

Variables	(1)	(2)	(3)	(4)	(5)	(6)
	cp	lngi	cp	cp	lngi	cp
mixdummy	0.039 ***	0.118 **	0.035 ***
	(4.14)	(2.23)	(3.74)
lngi			0.056 ***			0.056 ***
			(12.19)			(12.14)
mixrate				0.064 ***	0.527 ***	0.051 ***
				(3.38)	(4.91)	(2.66)
Constant	2.421 ***	−10.122 ***	2.688 ***	2.394 ***	−10.262 ***	2.663 ***
	(31.33)	(−24.51)	(33.49)	(31.04)	(−24.99)	(33.20)
Observations	6858	6858	6858	6858	6858	6858
F test	0	0	0	0	0	0

Note: ***, ** represent the significance levels of 1, 5%, respectively.

. From columns (1) and (4), it can be seen that mixed ownership reform has a significant positive correlation with carbon performance at the 1% level. According to columns (2) and (5), green innovation plays an intermediary role in the relationship between mixed ownership reform and carbon performance; according to columns (3) and (6), green innovation plays a partial intermediary role in the relationship between the two. The above research conclusions are consistent with the previous studies, Indicating the reliability of the research conclusions.

4.5. Endogenetic Test

4.5.1. Propensity Score Matching

The purpose of this paper is to investigate the effect of mixed ownership reform on carbon performance, that is, to reveal whether there is an actual causal relationship between mixed ownership reform and enterprise carbon performance. However, in reality, whether enterprises carry out mixed ownership reform is not random, but is determined by some factors. In order to alleviate the self-selection bias of samples, this paper uses the nearest neighbor matching 1:1 method to construct regression samples to further weaken the endogenous problem of selection bias [40]. Firstly, the sample enterprises are divided into two groups according to the existence of a mixed ownership structure and the median equity integration degree. The enterprises with mixed ownership structure and equity integration degrees higher than the median are defined as the experimental group. Secondly, enterprise size, asset–liability ratio, enterprise age, operating cash flow, tangible assets ratio, and growth as covariables to calculate the enterprise propensity to mixed ownership reform score, and the experimental group and the control group were matched. After matching, the absolute value of the standard deviation is no more than 10%, and the t statistic after matching is not significant; that is, there is no significant difference between the experimental group and the control group after matching.

Table 8. Propensity Score Matching.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixdummy	0.600 ***	0.414 ***
	(8.06)	(5.44)
d_mixrate			0.517 ***	0.299 ***
			(7.13)	(4.13)
Constant	8.353 ***	10.885 ***	8.389 ***	9.837 ***
	(157.50)	(16.91)	(163.99)	(15.56)
Controls	NO	YES	NO	YES
Year FE	NO	YES	NO	YES
Region FE	NO	YES	NO	YES
Observations	3552	3552	3738	3738
R-squared	0.018	0.184	0.013	0.164
F test	0	0	0	0
r2_a	0.0177	0.178	0.0132	0.159
F	64.93	33.15	50.85	30.39

Note: *** represent the significance levels of 1%.

shows the regression results after propensity matching score (PSM). It can be seen from the table that the coefficients of the mixed ownership structure and equity integration degree are significantly positive, indicating that the research results are still valid after considering the endogeneity.

4.5.2. Explanatory Variables Lag by One Phase

In order to further avoid the endogeneity problem between mixed ownership reform and carbon performance, this paper takes the mixed ownership structure and the degree of equity integration one stage behind [41].

Table 9. The explanatory variables lags in one stage.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
L.mixdummy	0.494 ***	0.305 ***
	(8.37)	(5.03)
L.mixrate			1.022 ***	0.586 ***
			(8.94)	(4.75)
Constant	8.492 ***	10.612 ***	8.427 ***	10.395 ***
	(227.24)	(20.96)	(204.44)	(20.55)
Controls	NO	YES	NO	YES
Year FE	NO	YES	NO	YES
Region FE	NO	YES	NO	YES
Observations	5971	5971	5971	5971
R-squared	0.012	0.146	0.013	0.146
F test	0	0	0	0
r2_a	0.0114	0.143	0.0131	0.142
F	70.02	44.23	79.99	44.09

Note: *** represent the significance levels of 1%.

shows the regression results of the independent variable lagging in one stage. It can be seen from the table that the mixed equity structure and equity integration degree are significantly positive at the 1% level, and the coefficients of the mixed equity structure and equity integration degree are 0.305 and 0.586, respectively. Compared with the mixed equity structure, equity integration degree has a greater effect on the improvement of carbon performance, which is consistent with hypothesis H1.

4.5.3. Eliminate Other Distractions

Although the above empirical results show that mixed ownership reform contributes to the improvement of enterprises’ carbon performance, it cannot be ruled out that some other factors may interfere with the relationship between mixed ownership reform and carbon performance [42]. In 2011, the National Development and Reform Commission of China issued a Notice on Launching Pilot Carbon Emission Trading Programs, requiring Beijing, Shanghai, Chongqing, Tianjin, Guangdong, Shenzhen, Hubei, and other provinces and municipalities to launch pilot carbon emission trading programs. This pilot policy may improve the carbon performance of local enterprises. In order to eliminate this interference factor, this paper deletes the sample enterprise data of the above provinces and cities after 2011 and re-conducts the fixed effect test. As can be seen from the regression results in

Table 10. Eliminate other distractions.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixdummy	0.579 ***	0.325 ***
	(9.32)	(4.95)
mixrate			1.143 ***	0.558 ***
			(9.64)	(4.23)
Constant	8.152 ***	11.153 ***	8.084 ***	11.035 ***
	(211.31)	(19.60)	(189.44)	(19.37)
Controls	NO	YES	NO	YES
Year FE	NO	YES	NO	YES
Region FE	NO	YES	NO	YES
Observations	5027	5027	5027	5027
R-squared	0.017	0.154	0.018	0.152
F test	0	0	0	0
r2_a	0.0168	0.150	0.0180	0.148
F	86.81	37.82	92.97	37.49

Note: *** represent the significance levels of 1%.

, after removing the samples that may interfere with the research results, the regression coefficients of mixed ownership structure and equity integration degree are significantly positive, which further ensures the robustness of the research conclusions.

5. Further Research

5.1. Heterogeneity Analysis

5.1.1. Heterogeneity Analysis of Industrial Pollution Degree

The heavy pollution industry has provided a lot of vitality for the rapid economic development of our country, but has also caused great pressure on the ecological environment. Due to the serious environmental governance problems in heavily polluting industries, it is easier to attract the attention of non-state-owned shareholders in the process of promoting mixed ownership reform, which may significantly improve carbon performance. In order to investigate the differences in the relationship between mixed ownership reform and the carbon performance of state-owned enterprises under different industrial pollution levels, in this study, the industries of sample enterprises were divided into heavy polluting industries and non-heavy polluting industries according to the Guidance on Industry Classification of Listed Companies revised in 2012, the Classified Management List of Environmental Protection Verification Industries of Listed Companies formulated by the Ministry of Environmental Protection in 2008 and the Guidance on Environmental Information Disclosure of Listed Companies. The regression results are shown in

Table 11. Industry pollution degree.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixdummy	0.539 ***		−0.169 ***
	(8.63)		(−3.47)
mixrate		0.942 ***		−0.286 ***
		(7.24)		(−2.95)
Constant	7.915 ***	7.324 ***	7.115 ***	7.132 ***
	(16.35)	(15.13)	(16.24)	(16.27)
Controls	YES	YES	YES	YES
Year FE	YES	YES	YES	YES
Region FE	YES	YES	YES	YES
Observations	3544	3544	3314	3314
R-squared	0.164	0.159	0.318	0.317
F test	0	0	0	0
r2_a	0.158	0.153	0.313	0.312
F	28.71	27.63	63.76	63.56

Note: *** represent the significance levels of 1%.

. From columns 1 and 2 of the table, it can be seen that the mixed ownership reform of enterprises in heavily polluting industries can help improve the carbon performance of enterprises. According to columns 3 and 4, in non-heavy polluting enterprises, mixed ownership reform significantly inhibits their carbon performance. In conclusion, compared with non-heavy polluting industries, the promotion effect of mixed ownership reform on carbon performance is more significant in heavy polluting industries.

5.1.2. Heterogeneity Analysis of Industrial Competitiveness

To some extent, the behavior and decision-making of enterprises are determined by the characteristics of the industry. The degree of industry competition refers to the monopoly degree and competition level of the industry in which an enterprise is located. When the competition level of the industry is high, on the one hand, the internal governance of the enterprise is relatively perfect, non-state-owned shareholders have a certain right to speak, and the mixed ownership reform has achieved remarkable results. On the other hand, enterprises face greater competitive pressure and have a strong incentive to enhance the level of green innovation through mixed ownership reform, so as to improve their carbon performance and enhance their competitiveness for sustainable development. Therefore, compared with monopolistic industries, the mixed ownership reform of Chinese enterprises in competitive industries has a stronger role in improving carbon performance. In order to investigate the difference in the relationship between mixed ownership reform and carbon performance under different industry competition degrees, this study uses the Hirschmann–Herfender index to measure industry competition degrees and divides all samples into monopoly industries and competitive industries according to the median of industry competition degrees, and then carries out regression according to Equation (1). The regression results are shown in

Table 12. Industry competition degree.

Variables	(1)	(2)	(3)	(4)
	cp	cp	cp	cp
mixdummy	0.175 **		0.453 ***
	(2.26)		(5.54)
mixrate		−0.011		1.111 ***
		(−0.07)		(6.66)
Constant	7.968 ***	7.821 ***	13.322 ***	13.078 ***
	(12.91)	(12.73)	(19.06)	(18.75)
Controls	YES	YES	YES	YES
Year FE	YES	YES	YES	YES
Region FE	YES	YES	YES	YES
Observations	3445	3445	3413	3413
R-squared	0.220	0.219	0.175	0.178
F test	0	0	0	0
r2_a	0.215	0.214	0.169	0.173
F	40.26	39.99	29.96	30.64

Note: ***, ** represent the significance levels of 1, 5%, respectively.

. The first and second columns are the regression results of monopolistic industries and the third and fourth columns are the regression results of competitive industries. In summary, the impact of mixed ownership reform on carbon performance is more significant in competitive industries than in monopolistic industries.

5.2. Extensive Research

Green Technology Innovation and Green Management Innovation

According to the above mediation test, green innovation plays a partial mediating role in the relationship between mixed ownership reform and carbon performance. Green innovation can be divided into two dimensions: green technology innovation and green management innovation, so whether these two dimensions play different roles in the relationship between mixed ownership reform and carbon performance remains to be paid attention to. Green technology innovation refers to technological innovation activities that bring economic and environmental benefits to enterprises by introducing new environmental protection knowledge and technology into production management. Current scholars show that green technology innovation is an important means to optimize environmental quality, solve environmental pollution problems, and promote ecological civilization construction in our country [43,44]. Green technology innovation can effectively control the use of carbon, provide corresponding technical support for the research and development and large-scale application of carbon dioxide capture and storage technology, generate the “technology dividend” effect, significantly reduce carbon emission levels, and promote the improvement of carbon performance [44]. At the same time, green technology innovation can improve the reputation and image of innovation subjects, enhance the market competitiveness of enterprises, and effectively enhance the economic performance of enterprises. Green management innovation refers to the innovative activities in which enterprises apply low-carbon and environmental protection management technologies and methods to improve resource utilization efficiency and environmental protection in production and operation and respond to the requirements of national environmental policies in order to achieve sustainable development. Green management innovation can change the internal factor allocation of enterprises and improve the sustainable development performance of enterprises. From the perspective of enterprises’ internal production and operation activities, the conservation concept of green management innovation will realize the efficient recycling and utilization of redundant resources. In this process, innovation activities with environmental protection objectives will also be generated to effectively reduce enterprises’ carbon emissions. From the perspective of the government, the implementation of green management innovation by enterprises can help management to weigh the benefits and costs of environmental protection and actively respond to the government’s environmental protection policies, so as to obtain environmental protection subsidies from the government, increase enterprises’ investment in environmental protection, accelerate the promotion of enterprises’ low-carbon projects, and empower the dual-carbon goal. From the perspective of core competitiveness, through green management technology and management methods, green management innovation conveys an important signal to the outside world that “enterprises can actively undertake social responsibilities”, produces a good reputation effect, creates a good image for enterprises, attracts employees with environmental awareness, and meets the green market demand of consumers, to improve their corporate green culture identification and help improve corporate carbon performance.

In order to deeply explore the difference between green technology innovation and green management innovation in the relationship between mixed ownership reform and carbon performance and clarify the deep mechanism of mixed ownership reform affecting carbon performance, this paper takes green technology innovation and green management innovation as the mediating variables to conduct a three-step mediation test. We use the number of invention patent applications to measure green technology innovation [45]. Five indicators were adopted to construct proxy variables of green management innovation, including whether to establish an enterprise environmental protection management system, whether to pass ISO14001 certification, whether to pass ISO9001 certification, whether to implement environmental protection education and training, and whether to implement environmental protection special actions [46]. When mixed ownership reform is measured by mixed equity results, the regression results are shown in

Table 13. Further mechanism analysis.

Variables	(1)	(2)	(3)	(4)	(5)	(6)
	cp	lngti	cp	cp	gm	cp
mixdummy	0.335 ***	0.049 **	0.307 ***	0.335 ***	0.015 **	0.329 ***
	(5.86)	(2.36)	(5.48)	(5.86)	(2.01)	(5.75)
lngti			0.575 ***
			(17.73)
gm						0.449 ***
						(4.75)
Constant	10.967 ***	−4.108 ***	13.330 ***	10.967 ***	−0.735 ***	11.297 ***
	(23.48)	(−24.12)	(28.02)	(23.48)	(−12.31)	(23.96)
Controls	YES	YES	YES	YES	YES	YES
Year FE	YES	YES	YES	YES	YES	YES
Region FE	YES	YES	YES	YES	YES	YES
Observations	6858	6858	6858	6858	6858	6858
R-squared	0.160	0.118	0.197	0.160	0.080	0.162
F test	0	0	0	0	0	0
r2_a	0.157	0.115	0.194	0.157	0.0768	0.159
F	54.10	37.97	66.89	54.10	24.78	53.00

Note: ***, ** represent the significance levels of 1, 5%, respectively.

. From columns 2 and 5 of the table, it can be seen that the coefficients of mixed equity structure and green technology innovation and green management innovation are 0.049 and 0.015, respectively, both of which are significant at the 5% level, indicating that compared with green management innovation, the mixed ownership structure has a stronger role in promoting green technology innovation. It can be seen from columns 3 and 6 of the table that the coefficients of green technology innovation and green management innovation and carbon performance are 0.575 and 0.449, respectively, both of which are significant at the 1% level, indicating that under the background of mixed ownership reform, green technology innovation has a greater effect on carbon performance than green management innovation.

When the mixed ownership reform is measured by the degree of equity integration, the regression results are shown in

Table 14. Further mechanism analysis.

Variables	(1)	(2)	(3)	(4)	(5)	(6)
	cp	lngti	cp	cp	gm	cp
mixrate	0.559 ***	0.175 ***	0.458 ***	0.559 ***	0.079 ***	0.524 ***
	(4.82)	(4.15)	(4.04)	(4.82)	(5.36)	(4.52)
lngti			0.574 ***
			(17.65)
gm						0.434 ***
						(4.59)
Constant	10.741 ***	−4.149 ***	13.121 ***	10.741 ***	−0.749 ***	11.067 ***
	(23.03)	(−24.43)	(27.58)	(23.03)	(−12.59)	(23.49)
Controls	YES	YES	YES	YES	YES	YES
Year FE	YES	YES	YES	YES	YES	YES
Region FE	YES	YES	YES	YES	YES	YES
Observations	6858	6858	6858	6858	6858	6858
R-squared	0.158	0.119	0.195	0.158	0.083	0.161
F test	0	0	0	0	0	0
r2_a	0.155	0.116	0.192	0.155	0.0802	0.158
F	53.55	38.52	66.21	53.55	25.90	52.40

Note: *** represent the significance levels of 1%.

. From the second and fifth columns of the table, it can be seen that the coefficients of equity integration and green technology innovation and green management innovation are 0.175 and 0.079, respectively, both of which are significant at the 1% level, indicating that compared with green management innovation, the degree of equity integration plays a stronger role in promoting green technology innovation. It can be seen from columns 3 and 6 of the table that the coefficients of green technology innovation and green management innovation and carbon performance are 0.574 and 0.434, respectively, both of which are significant at the 1% level, indicating that under the background of mixed ownership reform, green technology innovation has a greater effect on carbon performance than green management innovation. In conclusion, compared with green management innovation, mixed ownership reform has a stronger promoting effect on green technology innovation, and compared with green management innovation, green technology innovation has a greater impact on the improvement of carbon performance. Therefore, in the process of enterprise mixed ownership reform, green technology innovation and green management innovation should be promoted, and on this basis, the focus should be on the role of mixed ownership reform in guiding green technology innovation and the role of green technology innovation in improving carbon performance.

6. Conclusions and Implications

Based on the perspective of carbon performance, this paper discusses the relationship between mixed ownership reform and environmental sustainable development. The A-share industrial state-owned enterprises in Shanghai and Shenzhen from 2008 to 2020 are selected as the research samples. The research framework of the impact of mixed ownership reform on carbon performance is established, and the specific path of the impact of mixed ownership reform on carbon performance is defined. It provides a useful reference for promoting the mixed ownership reform of state-owned enterprises and accelerating the realization of the dual-carbon goal. In addition, the impact of mixed ownership reform on carbon performance in industries with different pollution levels and competition levels should be further clarified. The results show that: (1) the mixed ownership reform of state-owned enterprises can improve the carbon performance of enterprises; (2) green innovation plays a partial mediating role in the relationship between mixed ownership reform and carbon performance. Furthermore, compared with green management innovation, mixed ownership reform has a stronger promoting effect on green technology innovation, and green technology innovation has a greater impact on carbon performance. (3) The mixed ownership reform of state-owned enterprises in heavily polluting industries and competitive industries has a more significant effect on improving carbon performance.

6.1. Theoretical Contribution

This paper measures the mixed ownership reform of state-owned enterprises from the dual perspectives of “form” and “quality” and discusses the impact of mixed ownership reform on carbon performance reflecting the comprehensive environmental quality and its mechanism from this perspective. On this basis, the relationship between mixed ownership reform and mixed ownership reform is studied from the perspective of heterogeneity of industrial pollution degree and competition degree. It provides empirical evidence for the environmental governance effect of mixed ownership reform and provides a beneficial supplement for the influencing factors of carbon performance. Secondly, the paper analyzes the mechanism of green innovation in the process of the impact of mixed ownership reform on carbon performance, and further divides green innovation into two dimensions: green technology innovation and green management innovation, and compares the differences in different types of green innovation in the relationship between mixed ownership reform and carbon performance in a more systematic and comprehensive way. In addition, the impact of mixed ownership reform on the carbon performance of enterprises is discussed from the two aspects of industrial pollution degree and competition degree, which enriches the study on the sample heterogeneity of the relationship between mixed ownership reform and carbon performance.

6.2. Practical Contribution

Although the three-year soe reform campaign has come to an end and has achieved some results, it will be a protracted battle to push the mixed ownership reform forward. Based on the sustainable development goal of ecological civilization construction, this paper discusses the impact and mechanism of mixed ownership reform on environmental sustainable development from the perspective of carbon performance, and analyzes the impact of both from the perspective of the heterogeneity of industrial pollution degree and competition degree, providing a feasible path for enterprises to improve their carbon performance. At the same time, it also deepens the understanding of environmental governance of state-owned enterprises in different industries in the process of promoting mixed ownership reform, which has important practical significance for improving the carbon performance of enterprises and promoting the sustainable development of the environment.

6.3. Policy Implications

We discuss improving the reform of mixed ownership and promote classified governance of state-owned enterprises. The reform of mixed ownership should not only introduce non-state-owned shareholders but also establish a balance between state-owned equity and non-state-owned shareholders. When improving the reform of mixed ownership, it is necessary to implement the powers of the board of directors, deepen the construction of the board of directors, improve the ability of the board of directors to perform their duties, and actively promote the exercise of power by the management to form an effective equity balance. When promoting mixed ownership reform, it is necessary to promote the classification reform of state-owned enterprises, promote the concentration of capital in non-heavily polluting and low competitive industries, and guide the allocation of enterprise resources in green innovation activities to promote green innovation, reduce carbon emissions, and improve carbon performance.

6.4. Regulatory Implications

Environmental protection agencies should pay more attention to and invest in the environmental governance of industrial enterprises, provide relevant subsidies and tax incentives for green industries, provide financial support for R&D activities of enterprises, and reduce the risks of enterprises in the process of technological innovation. In addition, administrative and material penalties should be imposed on the pollution behaviors of polluting enterprises to increase the cost of pollution behaviors and restrain the generation of pollution behaviors. At the same time, the National Development and Reform Commission should improve the guarantee mechanism for green innovation, continuously improve the mechanisms for transforming, rating, and certificating green achievements, and stimulate the initiative of enterprises in non-heavily polluting and low-competitive industries in green innovation activities.

The conclusions of this paper have important practical implications for deepening the mixed ownership reform of state-owned enterprises, accelerating the realization of the dual-carbon goal, and helping the construction of ecological civilization in the new era. The conclusions are: (1) to continue to further promote the mixed ownership reform of state-owned enterprises and explore the establishment of a collaborative mechanism between the mixed ownership reform of industrial enterprises and the improvement of carbon performance. Mixed ownership reform should not only be mixed in “form” but also in substance. It should not only introduce non-state-owned equity, but also guarantee the “discourse right” of non-state-owned shareholders form certain equity checks and balances and improve the “quality” of mixed ownership reform. (2) Heterogeneous characteristics such as the degree of industrial pollution and the degree of competition have a different impact on the improvement of the carbon performance of the mixed ownership reform of state-owned enterprises. Therefore, enterprises should fully consider the industry heterogeneity in the process of promoting the mixed ownership reform. Given that mixed ownership reform in competitive industries has a stronger role in improving carbon performance, the government should improve the level of market competition and stimulate the vitality of the market, so as to accelerate enterprises to realize low-carbon transformation. Considering that mixed ownership reform in heavily polluting industries has a more significant role in improving carbon performance, heavy polluting industries should accelerate the process of mixed ownership and improve the quality of mixed ownership reform, so as to better play the role of mixed ownership reform in improving carbon performance. (3) State-owned enterprises should introduce non-state-owned shareholders to improve internal governance, give play to the integration role of heterogeneous resources, increase the investment in green innovation, promote green technology innovation and green management innovation of enterprises, and on this basis, focus on the guiding role of mixed ownership reform on green technology innovation and the role of green technology innovation in improving carbon performance.

In this paper, mixed ownership reform is measured from the dual perspectives of “form” and “quality”, and the impact of mixed ownership reform on carbon performance is not fully discussed from the perspective of shareholder heterogeneity. Next, from the perspective of shareholder heterogeneity, we can empirically test which shareholders can improve the carbon performance more significantly by introducing them into state-owned enterprises, so as to provide guidance for China’s state-owned enterprise reform.