The main purpose of the study is to test whether CSR performance and default risk have a negative relationship with each other. Since we are investigating the Korean stock market, the CSR data measured by the ESG score was obtained from the KCGS (Korea Institute of Corporate Governance and Sustainability), whereas the financial data to calculate the default risks and all the control variables were acquired from two data providers, the FnGuide database and CRI (Credit Research Initiative) database.
3.1.1. Corporate Social Responsibility
The definition of CSR and its scope are very diverse and lack uniformity. To measure CSR, some studies use the standardized ESG scores provided by international data collecting agencies, such as Bloomberg, Thomson Reuters Eikon, and the MSCI KLD index, to minimize measurement bias. The KLD index is the most widely used data source and has been commonly utilized in recent studies [
15,
47]. However, these databases have limitations as they do not offer detailed ESG information about Korean companies [
17]. To examine the Korean market, most previous studies have used the KEJI index provided by Korea Economic Justice Research Institute [
13,
16,
18,
31] and KCGS (Korea Institute of Corporate Governance and Sustainability) [
15,
17,
18,
37,
48,
49].
We collected the ESG data from KCGS considering that this database has a key advantage over other databases in Korea. Since it examines all the KOSPI-listed companies and selected KOSDAQ companies, it provides wider coverage of Korean firms’ ESG data t the other index, KEJI, which has been mainly used in previous studies. Unlike KEJI, which only provides data on 200 annual firms, usually large-size firms [
15,
17], the KCGS database covers information on approximately 900 firms [
14]. Furthermore, the latter’s ESG scores are used in several SRI indexes in the Korea Stock Exchange (KRX) [
37]. Based on KCGS, the ESG scores of Korean firms, as well as each firm’s environmental, social, and corporate governance practices, have been available since 2011. The score of a firm’s environmental performance is evaluated based on categories such as environmental management, performance, and stakeholder relations. The social performance score is reviewed based on categories including suppliers and competitors, consumers, and the local community. The corporate governance score is evaluated based on categories such as shareholder rights protection, the board of directors, auditing body, and disclosure.
There are underlying reasons why prior studies have suggested adopting ESG scores as a proxy for CSR performance. The KCGS database only disclosed the letter grade of a company’s CSR performance, without providing detailed scores, prior to 2010. Since 2011, both the letter grade and numeric score data have been made available. However, the limitation of the ESG letter-grade-based system is that researchers cannot accurately determine a firm’s exact CSR score within a specific letter grade. [
17]. For example, grade “A” of a firm refers to a specific range of ESG total scores, starting from 4.50, 4.55, and 4.60 to 5.45. On the other hand, using the ESG scoring system as a proxy for CSR performance could explicitly reflect the value of CSR performance. KCGS data offers access to numeric scores on which the letter-grade ratings are based [
14]. Therefore, based on prior studies that have employed ESG scores as their proxy for CSR performance [
17,
37,
50], this study also adopted the ESG score as a proxy for the CSR variable. The overall ESG score used in this study specifically refers to the final score provided by KCGS.
Table 1 shows the statistics overall ESG scores and each ESG component score by year. The final sample of this study is an unbalanced panel of data on 6977 firm-year observations, reflecting 958 unique Korean firms (excluding financial firms) between 2011 and 2020. Of note is that the ESG score was obtained from KCGS data. The overall score, which is used in this study, refers to the final score provided by KCGS. The detailed formula and weights used by KCGS to calculate overall ESG performance are not publicly disclosed [
14]. As a result, our study provides environmental, social, and governance scores, which are partially scaled down to 1:100 for calculation purposes [
51]. A higher score for ESG indicates better ESG activities by the companies. On average, the highest and lowest ESG scores found in 2014 and 2012 were 2.86 and 1.97, respectively.
The environmental score, which reflects how firms take actions to protect and minimize damage to the environment, had the same highest score in 2013 as in 2014, which was 0.42. However, since 2015, a downtrend steadily happened until 2020. The social score represents how firms treat their employees and the communities they serve. Between 2011 and 2016, the average social score gradually fluctuated. Although it significantly dropped in 2017, a steadily increasing trend was shown in the subsequent years. The governance score reflects how firms’ managements direct and supervise their organizational authority. The average score slightly fluctuated until 2014 and suddenly bottomed out in 2015. However, since 2016, the trend gradually increased.
3.1.2. Default Risk
Based on a wide body of prior studies, there are two commonly used approaches to measure a firm’s default risk. The first approach is an accounting-based model [
19,
52,
53,
54,
55,
56], and the second approach is a non-accounting-based model, namely a market-based model [
57]. Many preceding works have predicted financial distress risk by applying accounting and market-based measurements [
53,
58,
59]. To calculate default risk, our study adopted two accounting-based measures (Z- and K-score) and a market-based measure (DTD). The Altman Z-score was the primary proxy for the analysis, while the K-score and Distance to Default (DTD) served as robustness tests.
As an accounting-based measurement, the Altman Z-score has been used as the main proxy for default risk by previous studies. However, there are differing perspectives regarding the use of the Z-score as a measure of distress or default risk. Although the Z-score by Altman surpasses the hazard and other models to predict a firm’s bankruptcy using an international dataset [
60,
61], the accounting statements are of limited sufficiency since they are formulated on a going-concern basis [
62]. Other works have criticized the Z-score as a not-really-fit model, stating that the coefficients in the Z-score calculation weaken the predictive ability to the point where it does not perform better than its most predictive predictor ratio [
63,
64]. Despite differing views, a significant amount of literature still features the use of the Z-score model as the primary essential proxy in the research [
53,
58,
59].
To obtain more meaningful results and increase the robustness of the analysis, two other proxies for measuring the default risk of the firm, the K-score and the Distance to Default (DTD), were used in this study. We obtained financial data from two data providers based on the default risk measurements. Data for the first two proxies (the Z-score and K-score) were derived from the FnGuide database as the reliable and comprehensive data provider for the Korean stock market. Meanwhile, data for the DTD measurement were collected from the CRI database by the National University of Singapore’s Risk Management Institute (RMI). This database has been used in prior studies that have focused on default risk [
25].
Z-score by Altman (1968) [
52]
The first model to address the research problem is the Altman Z-score, 1968, as an accounting-based model. The equation of the Z-score is formulated as follows [
52]:
where Z is the Z-score, X1 is the working capital/total assets, X2 is the retained earnings/total assets, X3 is the earnings before interest and taxes/total assets, X4 is the market value of equity/market value of total liabilities, and X5 is the sales/total assets. Each X1 to X5 reflects the liquidity, profitability, leverage, solvency, and activity of the firm. According to this model, a firm is predicted to fall into “the safe zone or strong financial condition” when the score is higher than 2.99, whereas it is predicted to fall into “the distress zone or high probability of bankruptcy” when the score is lower than 1.81. To explain the negative relationship between CSR and default risk, we multiply the Z-score by −1 (negative one) as a measure of financial distress risk. It is important to confirm that a greater negative value for the Z-score variable suggests a lower level of default risk.
- 2.
K-score by Altman et al. (1995) [
19]
We adopt another bankruptcy model, which was established particularly for a sample set of Korean companies by Altman et al. in 1995, as the alternative test of this study. According to their study, there are two model classifications established for the Korean market. The first model, the K1-score, is used only for public and private firms, whilst the second model, the K2-score, is used for publicly traded firms [
19]. These accounting-based models perform with excellent accuracies in the first two years before the default. Since the sample of this study focuses on publicly traded Korean firms, we adopted the K2-score model and we simplified the terms of this model as the K-score. The formula is written as follows:
where K-score represents K2-score as a default risk’s proxy, X1 is log (total assets), X2 is log (sales/total assets), X3 is retained earnings/total assets, and X4 is the market value of equity/total liabilities. X1 to X4 represents the size, asset turnover, profitability, and leverage of a firm. Under this model, when the score is higher than 0.75, the firm is determined as “sound firm or strong financial health”, whereas when the score is lower than −2.3, the firm is determined as “insolvent firm or high probability of bankruptcy”. Using the same approach as the previous model, we multiplied the K-score by −1 (negative one) to evaluate the default risk. A greater negative value for the K-score variable suggests a lower level of default.
- 3.
Distance to Default (DTD)
Lastly, we utilized distance-to-default (DTD) as a market-based model that has long been observed as an essential indicator of a firm’s credit quality in relation to the default risk. It is determined by using Merton’s structural model [
20], assuming that the firm value follows the Wiener process. The equity value, as a function of the total firm value, can be described by the Black–Scholes–Merton formula [
65]. The default exists only if the value of the firm is less than the face value of debt, and it will happen only during the maturity period. The formula of DTD is defined as follows:
where
is the asset value reflecting a geometric Brownian motion with drift (
) and volatility (
), and
L is the default point. There have been many variants of this model to estimate. We download the data estimated by NUS-CRI. NUS-CRI modifies the model by doing certain treatments on its own DTD computation to address the several drawbacks. It is not easy to estimate the
with reasonable precision unless the very long time span of data is calculated [
66]. The expression of the DTD forming by NUS-CRI is:
where the default point is
, and the maturity of liabilities is set to one year. For more details, refer to the CRI technical report on the CRI website.
Theoretically, firms with higher DTDs will have lower default risks. Using the same approach as the two previous models, we multiplied the score by −1 to be consistent with the other measures used; a greater negative DTD score suggests a lower default risk level.
Table 2 shows the average value of each proxy of default risk, which is measured by the Z-score, K-score, and DTD, by year. As we explained before, considering a non-direct effect of a firm’s CSR activities on default risk, we assume that the default risk at the end of time t + 1 is predicted by the CSR performance at the end of time t. Thus,
Table 2 shows the proxies of default risk statistics from 2012 to 2021 including the mean, standard deviation, minimum, and maximum values of the distribution across companies. The sample comprises 6977 South Korean firm-year observations for the sample period. As stated earlier, the negative values for the Z-score, K-score, and DTD are determined to explain the negative relationship between CSR and default risk by multiplying the proxies by −1 (negative one). The high negative score refers to the low risk of default.
Moreover, in consonance with prior studies [
2,
67], a set of control variables that influence a firm’s default risk were included and explained in this study.
The market-to-book value (MTB) is the comparison ratio between the market value of equity and the book value of equity. Based on prior studies, it was used as a proxy for a firm’s growth opportunities. High-growth opportunity firms have promising prospects and are more attractive to investors [
2]. Therefore, we anticipate an inverse association between MTB and a firm’s default risk. In this study, by multiplying the proxy of default risk by −1, we expect the MTB to have a negative association to the minus Z-score.
Volatility (VOL) reflects the amount of uncertainty related to the extent of changes in a firm’s value. High volatility means that a firm’s value can potentially change dramatically in either direction over a period. It is measured by computing the standard deviation of monthly stock returns over the year. Thus, we assume a positive relationship between volatility and default risk [
68]. In this study, by multiplying the default risk by −1, we expect a positive association between VOL and the minus Z-score.
The stock return (RET) shows the ability of a firm to maximize the wealth of its shareholders. It describes the average of the firm’s monthly return over the year. Providing a higher stock return means that a firm is less likely to have a distress risk. Therefore, we expect RET to have a negative relationship with default risk, which means that by multiplying the default risk by −1, we expect a negative relationship between the RET and the minus Z-score.
Financial slack (SLACK) is the comparison between cash and cash equivalents and the firm’s total assets. High financial slack refers to less dependency on external financing, which leads to less debt. Accordingly, we expect that SLACK has an inverse relationship with default risk. By multiplying the default risk by −1, we expect a negative link between SLACK and the minus Z-score.
The size of the firm (SIZE) is derived from the natural logarithm of the firm’s total assets. It reflects how big or small is the scale or volume of a firm’s operation. Larger firms are likely to have higher debt ratios, which lead to a higher opportunity for distress [
2,
67]. Thus, we anticipate that SIZE has a positive relationship with default risk, which means that by multiplying the default risk by −1, we expect a positive link between SIZE and the minus Z-score.
Asset tangibility (TANG) refers to physical measurable assets that are utilized in a firm’s operations. It is measured by calculating the percentage of total fixed assets of a firm that contribute to its total assets. Theoretically, having more tangible assets will enhance the ability of the firm to collateralize its debt and could produce higher debt financing [
69]. In this study, a positive relationship between asset tangibility and a firm’s default risk is expected to exist. In other words, by multiplying the default risk by −1, we expect a positive association between TANG and the minus Z-score.
Table 3 presents the descriptive statistics of the dependent and independent variables, as well as the control variables. The sample consists of 6977 South Korean firm-year observations of the sample period.
Table 4 reports the examination of the multicollinearity problem between explanatory variables using a Pearson correlation analysis by following the prior study’s test [
2]. Each ESG component shows a positive and high correlation with the aggregate ESG score, reflecting that these components contribute to firms’ ESG. Based on the table, no correlation value exceeds 59% (RET and VOL) between control variables. Furthermore, a variance inflation factor (VIF) computation is also conducted to test the absence of a multicollinearity problem. The larger the VIF value, the more “troublesome” or collinear the variable independent. As a rule of thumb, if the VIF value exceeds 10, that variable is indicated as highly collinear [
70,
71]. In other words, a VIF above 10 indicates that a multicollinearity problem might exist, and even some studies suggest a VIF value above 5 indicates that a multicollinearity problem exists [
72]. As reported in the table, the highest VIF value was 3.21, which belongs to the ESG score, indicating that multicollinearity problems did not exist in this study.