1. Introduction
The increase of debt cost will lead to the debt default risk of enterprises, which will be reflected in the additional investment risk compensation demanded by creditors, thus resulting in a vicious circle of corporate financial risk [
1]. In addition, the increase of debt cost may have a significant impact on investment strategies, investment decisions and sustainable development of enterprises [
2]. Under the impact of the global COVID-19 pandemic, the risk of debt default in the real economy has obviously accumulated. However, under the condition of balanced operating capital payment, the debt default boundary is jointly determined by operating efficiency, borrowing rate and capital structure [
3]. Operation efficiency management is the key strategy of enterprise development, mainly to create shareholder value as the ultimate goal. However, operational efficiency exerts its own utilization value in the operation of enterprises and affects the business performance of enterprises [
4]. Improving the operation efficiency management can increase profitability and profit quality, thus having a significant impact on the cost of debt [
5].
As environmental issues brought by economic development have increasingly become a hot topic discussed by scholars and a common challenge faced by countries around the world, enterprises and creditors have begun to pay attention to the climate change risk [
6]. The carbon information disclosure enables stakeholders to obtain more information, so as to promote the smooth progress of carbon emission trading, obtain excess returns and enhance corporate value [
7]. Climate-related information disclosure can reduce the information asymmetry between enterprises and creditors, thus reducing the capital cost for enterprises [
8]. Therefore, in combination with scholars’ studies on the relationships among operational efficiency, carbon information disclosure and enterprise value, operational efficiency and debt cost, and carbon information disclosure on debt cost, this study assumes the relationship among operational efficiency, carbon information disclosure and debt cost: If operational efficiency can affect the debt cost, does carbon information disclosure play an intermediary role? In addition, compared with enterprises in low-carbon industries, the value of enterprises in high-carbon industries is more affected by carbon emission trading, and their market value will be further reduced [
9]. Both the green credit policy and the development of green credit increase the debt financing cost of “high-pollution and high-emission” enterprises, but reduce the debt financing cost of green enterprises [
10]. This study argues that the operating efficiency and enterprises carbon information disclosure in different carbon-intensive industries may have different impacts on corporate debt costs. The following research questions are put forward: 1. Does operational efficiency have a positive impact on carbon information disclosure? 2. Is there a significant positive correlation between operational efficiency and carbon information disclosure? 3. Does carbon information disclosure play an intermediary role in the relationship between operational efficiency and debt cost?
The results show that the higher the operating efficiency of high and low carbon enterprises, the lower the debt cost. The enterprises carbon information disclosure in low-carbon industries has a significant partial mediating effect on the relationship between operational efficiency and debt cost. The mediating effect of carbon information disclosure on the relationship between operational efficiency and debt cost in carbon-intensive industries is not significant. It verifies that the operating efficiency of low-carbon industry can affect the cost of debt through carbon information disclosure, and finds a significant correlation between carbon information disclosure and operating efficiency. This study broadens ways for enterprises in low-carbon industries to reduce debt costs, highlights the role of operational efficiency, and reveals the significant effects of carbon information disclosure. This has implications for the research on the relationship between operational efficiency, debt cost of different carbon-intensive enterprises and carbon information disclosure, especially the complex relationship between operational efficiency and debt cost of carbon-intensive industries.
2. Literature Review
2.1. Operational Efficiency and Cost of Debt
Operational efficiency, as part of the creditor’s assessment of the debtor’s ability to repay debts, is the basic factor for debt cost reduction, so it is necessary to grasp the balance between operational efficiency and debt cost. In terms of influencing factors, Rey et al. believe that the cost advantage is a factor that directly affects the rapid improvement of operational efficiency of Asian airlines [
11]. Studies such as that by Barros et al. show that a company’s operational efficiency is affected by the size of the company, mergers and acquisitions, and timing [
12]. In terms of research methods, Saranga and Nagpal determined the driving factors of operational efficiency and carried out factor analysis through the DEA model combined with GLS regression and the Tobit model [
4]. Ramachandran and Janakiraman comprehensively calculated operational efficiency through the performance index, efficiency index and utilization index [
13]. In addition, Seth et al. used the data envelopment analysis method to evaluate the relative effectiveness of multi-index input and multi-index output [
14].
Low-cost debt financing is the core factor for enterprises to have competitive advantages. The existing research on the cost of debt mainly analyzes the factors affecting the cost of debt from three aspects: the quality of information disclosure, the characteristics of the external environment and the characteristics of internal governance. Since information asymmetry is an important factor affecting the cost of debt, low-quality environmental information disclosure will lead to an increase in corporate debt costs [
15]. The industry environment characteristics [
1], legal system [
16] and media reports [
17] will all have an impact on the cost of debt of enterprises. From the perspective of the degree of competition in the industry environment, a good competitive environment in the industry environment is conducive to reducing debt costs, and this effect is more obvious in private enterprises. In terms of internal governance characteristics, previous studies have mainly focused on the role of institutional arrangements [
18], internal culture [
19] and senior management characteristics [
20] on debt costs. There are few studies on the impact of operating efficiency on debt costs, and the research content is mainly focused on internal control defects. The lower the enterprise’s operating efficiency, the greater the financial exposure, and the more sensitive the debt cost is to the company’s performance [
21]. Therefore, reasonable debt cost is an indispensable core link to improve operational efficiency. Although there are many studies on the cost of debt at present, the research on the relationship between corporate operating efficiency and debt cost is still in the exploratory stage.
2.2. Operational Efficiency and Corporate Performance
Enterprise performance is the real result of enterprise operation, which is usually measured by the unit input cost or the profit brought by the unit output that reflects the production result [
22]. As an important indicator to measure the financial efficiency and corporate performance of an enterprise, operational efficiency represents the relationship between liquidity and profitability [
23,
24,
25]. However, blindly pursuing operational efficiency will also reduce actual business efficiency and further reduce enterprise performance [
26]. Therefore, how to measure the impact of an enterprise’s operational efficiency on enterprise performance has become a hot topic in academic circles. The existing research mainly analyzes the profitability of listed companies through financial reports, and further measures the impact of corporate operating efficiency on company performance through financial indicators such as total asset turnover rate, current asset turnover rate and accounts receivable turnover rate [
27].
However, scholars hold different views on the specific impact of operational efficiency on corporate performance. Some scholars have found that the total asset turnover rate [
28], current asset turnover rate [
29] and accounts receivable turnover rate [
30] have a positive impact on corporate profitability and further have a positive effect on corporate performance. On the contrary, another group of scholars has found that there is a negative correlation between corporate operating efficiency and corporate performance. In terms of profitability, the average payback period, inventory turnover rate and cash cycle are negatively related to corporate performance [
31,
32,
33]. Furthermore, some studies show that asset liquidity, cash turnover and accounts receivable turnover do not significantly affect the profitability and performance of enterprises [
34]. Operational efficiency is the internal performance of the company’s operation, while corporate performance is the external performance of the company’s operation. The relationship between the two needs to be further confirmed and studied.
2.3. Corporate Performance and Carbon Information Disclosure
In recent years, with the enhancement of environmental regulations, carbon information disclosure, as an important way for enterprises to transmit their carbon performance and carbon emission management to the outside world, has been highly valued by external stakeholders and has become an important issue in the field of economic management. By sorting out the existing literature, the research on carbon information disclosure mainly focuses on the relationship between corporate environmental responsibility and corporate performance. A review of previous literature shows that factors that significantly affect corporate carbon information disclosure include corporate size, institutional shareholding, corporate performance and social reputation [
35]. Most of the research results show that corporate performance will be positively affected by carbon information disclosure [
36]. Some studies show that corporate carbon information disclosure will reduce investors’ uncertainty [
37], alleviate financial constraints [
38], obtain practical economic benefits and further improve corporate performance [
39], and this promoting effect is more obvious in non-state-owned enterprises and enterprises with high corporate governance level [
40].
However, some scholars have found that carbon information disclosure is negatively related to corporate performance. As enterprises fulfill their environmental responsibilities, they will inevitably pay certain corporate costs, which will reduce corporate performance. Therefore, the disclosure of carbon information is not conducive to the improvement of corporate performance [
41]. In addition, the disclosure cost is relatively high. This measure cannot provide good economic benefits for related enterprises, even reduces the profitability of enterprises, and further hurts corporate performance [
42]. Sheng et al. also found that carbon information disclosure will inhibit the realization of corporate value under the product market after a series of research and analyses [
43]. In summary, the relationship between carbon information disclosure and corporate performance is still worth further exploration under different conditions.
2.4. Carbon Disclosure and Cost of Debt
The research on the relationship between information disclosure and debt cost initially extended from accounting information disclosure to social responsibility information disclosure and environmental information disclosure. With the development of China’s carbon trading market, the research on carbon information disclosure has gradually deepened. The existing literature mainly explores the relationship between carbon information disclosure and corporate value, financial performance and capital costs. Research on the relationship between carbon information disclosure and corporate debt costs is still lacking in depth.
The concept of carbon information disclosure was first proposed by Clarkson et al. [
44]. Scholars divide companies into two types according to the degree of environmental information disclosure. Companies that strictly abide by environmental information disclosure increase the cost of competitor information disclosure, while companies that minimize environmental information disclosure expenditures do not enjoy the benefits of carbon information disclosure. With the improvement of environmental regulations, creditors will increase their concerns about corporate carbon risks and factor climate change risks into their credit decisions [
45]. Subsequently, companies that choose to voluntarily disclose carbon emissions enjoy more favorable loan terms than companies that do not disclose carbon emissions [
38].
Some companies have lower financing costs, but their carbon information disclosure shows a higher level [
46]. Scholars have begun to analyze the internal mechanism of the above phenomenon: Lemma et al. found that the improvement of carbon information disclosure can effectively improve the transparency of enterprises, effectively alleviate the degree of information asymmetry between enterprises and creditors and enable creditors to have a deeper understanding of the carbon performance of enterprises, thus reducing financing costs [
47]. In addition, Fonseka et al. found that environmental information disclosure helps to establish a good image for enterprises to comply with environmental laws and regulations, send signals to creditors that their production and business activities have obtained legal status, enhance creditors’ confidence in the legal operation of enterprises and thus reduce debt costs [
48]. Palea and Drogo also found that high carbon emissions were associated with high debt financing, and the improvement of carbon information disclosure played a role in mitigating the cost of debt [
8].
2.5. Operational Efficiency, Carbon Disclosure and Cost of Debt
Under the concept of global governance of advocating the awareness of a community with a shared future for mankind, the national low-carbon strategy and green credit policy are continuously being carried out in depth. To reduce their indirect risks, investors use the information disclosed by corporate carbon information as an important reference for financing decisions [
38]. Capital is the source of sustainable development of enterprises, and debt financing is one of the main channels for enterprises to obtain external capital. How to improve enterprises’ financing ability and reduce debt costs while complying with national policies and undertaking social responsibility, to achieve win-win results in enterprise operation benefits, environmental benefits and economic benefits, is an important research topic.
However, in terms of the research on the quality of carbon information disclosure, at the beginning of the period, limited carbon information disclosure usually hinders investors from making a comparison [
49], and some enterprises are often not willing to take the initiative to disclose information due to light environmental pollution. In the long run, it may aggravate the information asymmetry inside and outside the enterprise, and the external stakeholders of the enterprise cannot accurately judge the future operating benefits and risks of the enterprise, thus leading to adverse selection and further increasing the debt cost of the enterprise [
50].
Under the threat of global warming, more and more attention has been paid to the guarantee of carbon information disclosure [
51], but there is still a lack of consistency in the indicators of quantitative carbon information disclosure. Some scholars conduct research through CDP’s carbon disclosure leadership index [
52], other scholars develop carbon disclosure index according to the carbon reporting framework [
53] and some scholars evaluate through carbon emission level [
54].
At present, there have been preliminary studies on the relationship among corporate operating efficiency, carbon information disclosure, and cost of debt in academic circles at home and abroad, but there is a lack of research on the relationship between carbon information disclosure and the cost of debt through operating efficiency. Therefore, considering the relationship among corporate operating efficiency, carbon information disclosure and cost of debt can enrich the research on the relationship among the three.
In summary, the research progress of the relationship among operational efficiency, carbon information disclosure and cost of debt is summarized. However, there are differences between the conclusions found in the study, which may be caused by different research samples, research methods and research indicators. In addition, there are few studies on the relationship among operational efficiency, carbon disclosure and cost of debt. By examining the mediating effect of carbon disclosure in the relationship between operational efficiency and debt cost, this study attempts to overcome the above-mentioned defects, and use the important influencing factor of operational efficiency to explore the mechanism between carbon information disclosure and debt cost, to enrich the research on carbon information disclosure.
3. Research Hypothesis
In recent years, with the increase of carbon emissions year by year, climate extreme events such as global warming and glacier melting have revealed deep-seated problems for human beings and the environment. As a major participant in market operations, enterprises should bear the social responsibility of environmental protection, energy conservation and emission reduction. Especially under the promotion of the carbon peak and carbon neutrality policy, enterprises in both carbon-intensive and low-carbon industries are facing a series of regulations and social public opinion pressure. In addition to fulfilling social obligations, enterprises also need to deal with issues such as enterprise operation efficiency and debt financing. Operational efficiency is a part of the creditor’s evaluation of the debtor’s solvency, and the relationship between the two is worth exploring.
According to the stakeholder theory, the production and operation of an enterprise are closely related to its shareholders and creditors. In the process of the whole life cycle management of internal assets, if the enterprise does not pay enough attention to some assets, the operation efficiency is low and ineffective assets occupy more, which will further affect the creditor’s investment decision-making and easily affect the financing cost of the enterprise. Specifically, companies operate less efficiently, and investors will underestimate their value as a signal of high risk, thus increasing the difficulty of corporate financing and further increasing the cost of debt [
55]. However, some studies believe that starting from the preferred order financing theory, higher operating efficiency of an enterprise means having high liquidity assets, which can be understood as hedging of debts in essence [
56]. Considering practical value and potential need from investors, this study tends to value rather than undermine liquidity assets, regardless of industries. Therefore, based on the above analysis, this article proposes Hypotheses 1 and 2:
H1: In carbon-intensive industries, the higher the operational efficiency, the lower the cost of debt.
H2: In low-carbon industries, the higher the operational efficiency, the lower the cost of debt.
As climate change has received more and more research and policy attention, the public’s understanding of the carbon peaking and carbon neutrality goals has been deepened; the concept of green, low-carbon and circular economy has been deepened; and the level of carbon information disclosure has become a powerful indicator to measure the response of enterprises to climate change [
57]. The study found that enterprises in carbon-intensive industries are more inclined to provide high-quality carbon information disclosure levels. The main reasons are as follows: First, if enterprises in carbon-intensive industries cannot disclose high-quality carbon information, creditors will think that the enterprise’s operating efficiency is poor and there is investment uncertainty, thus reducing the purchase preference for enterprises, and the enterprise’s debt cost will increase. Second, carbon information disclosure reflects the social responsibility of enterprises in carbon-intensive industries and their determination to respond to environmental protection and emission reduction policies. If enterprises in carbon-intensive industries do not actively respond to the national carbon reduction policy and disclose low-quality carbon information to the outside world, investors will think that enterprises have performed their social responsibility poorly, thus losing investment trust in them and restricting investment in enterprises. Further, the financing difficulty of enterprises increases, the cost of debt increases, the working capital is limited and the operating efficiency will also be adversely affected. Therefore, this article proposes Hypothesis 3:
H3: Carbon disclosure has a mediating effect on the relationship between operational efficiency and debt cost in carbon-intensive industries.
In addition, other studies have found that lenders mitigate the impact of greenhouse gas emissions of companies in carbon-intensive industries on their future cash flows, but also require companies with higher carbon emission intensity to pay significantly higher costs to finance their operations through debt [
58]. Therefore, based on the above analysis, this article proposes Hypothesis 4:
H4: Carbon disclosure has no mediating effect on the relationship between operational efficiency and debt cost in carbon-intensive industries.
According to the signal transmission theory, information asymmetry in the capital markets will aggravate the degree of external financing constraints of enterprises. When investors cannot well receive the information disclosed by enterprises, they will be stricter on the operating efficiency and financing behavior of enterprises to reduce investment losses [
59]. The study found that low-carbon industry enterprises are more inclined to provide high-quality carbon information disclosure levels. The main reasons are as follows: First, voluntary carbon information disclosure by low-carbon industry enterprises reduces the adverse impact of information asymmetry between investors and enterprises, and then reduces regulatory costs. Second, the disclosure of carbon information of enterprises in low-carbon industries also shows good operating efficiency and operating conditions to the public, improves investors’ purchase preference for enterprise products, reduces the difficulty of enterprise financing, is conducive to the reduction of enterprise debt costs, and further improves the operating efficiency of enterprise funds. Third, carbon information disclosure reflects the determination of enterprises in low-carbon industries to fulfill their social responsibility and respond to environmental protection and emission reduction policies, while avoiding negative market reactions caused by concealing carbon information [
47]. Therefore, this article proposes Hypothesis 5:
H5: Carbon information disclosure has a mediating effect on the relationship between operational efficiency and debt cost in low-carbon industries.
However, some studies believe that low-carbon industry enterprises face fewer legitimacy problems, and investors are not sensitive to the degree of carbon information disclosure of such enterprises, so the relationship between operational efficiency and debt cost is weak for low-carbon industry enterprises [
60]. Therefore, based on the above analysis, this article proposes Hypothesis 6:
H6: Carbon information disclosure in low-carbon industries has no mediating effect on the relationship between operational efficiency and debt cost in low-carbon industries.
6. Discussion and Conclusions
The results show that there is no significant mediating effect of carbon information disclosure on the relationship between operational efficiency and debt cost in high-carbon industries. However, this intermediary effect exists in low-carbon industry, and it is a partial intermediary effect. This may indicate that the carbon disclosure of low-carbon industries is more closely related to the cost of debt. The deep reason may be that compared with the carbon-intensive industry, the carbon information disclosure of enterprises in low-carbon industry can reflect the enthusiasm of enterprises in their own financing or the restrictive channels of enterprise carbon performance evaluation. However, for enterprises in high-carbon industries, their financing is more complicated in terms of enterprise scale, profitability, future development ability and relational capital. This is why carbon information disclosure of enterprises in high-carbon industries has little impact on the relationship between operational efficiency and debt cost.
The operational efficiency (total asset turnover, etc.) of enterprises in different carbon-intensive industries has a similar positive impact on the cost of debt. The positive value of carbon information disclosure of enterprises in low-carbon industries provides favorable evidence for enterprises to make carbon information disclosure. However, promoting the link between carbon information disclosure and debt cost of enterprises in high-carbon industries will help enterprises in the future to create carbon information transparency or voluntary carbon information disclosure. It is of great significance for regional and industrial enterprises to choose the disclosure system of voluntary or mandatory carbon information disclosure.
Given that this study has explored the internal relationship between operational efficiency, carbon information disclosure and debt cost, the ratio of fixed assets is only a control variable, and the alternative variables of operational efficiency are still few. The fixed asset ratio can be an important distinction between high-carbon and low-carbon industries. Considering the complexity of operational efficiency, quick ratio and other operational indicators should be given some attention. With deeper consideration of the insignificant impact of carbon information disclosure on the relationship between operational efficiency and debt cost of enterprises in high-carbon industries, future studies should investigate the level of debt of enterprises in high-carbon industries to make conclusions on relationship between carbon information disclosure and certain debt cost characteristics of enterprises. In addition, future studies need to distinguish between debt cost and equity cost, so as to have a deeper understanding of the influencing mechanisms of operational efficiency, environmental information disclosure and debt cost.