4. Robustness Tests
4.1 Propensity score matched (PSM) sample
Prior literature in CDS stream (e.g., Subrahmanyam et al., 2014; Chang et al., 2019) documents
that firms selected to be referred for CDS trading are generally larger and more mature, more
informationally transparent, and possess better creditworthiness. This fact is consistent with lemon
effects. Comparing with CDS buyers, CDS sellers face an information disadvantage regarding the
referenced firms because CDS buyers are generally loan originators or bondholders, and thus hold
private information of the borrowers. Therefore, CDS sellers prefer to trade trustworthy companies
that are less opaque and larger in market value by way of reducing transaction risk. It is possible
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performance. To address those concerns, I follow the literature (Ashcraft and Santos, 2009;
Subrahmanyam et al., 2014; Martin and Roychowdhury, 2015; Chang et al. 2019) to form matched
control firms that have never been selected to trade CDS throughout the whole sample period.
I use the following probit model to capture the likelihood of CDS trading each year.
ππππ(πΆπ·ππΌππΌππ,π‘ = 1) = β (πΌ + πππ,π‘β1+ ππΌπππ’π π‘ππ¦π + π½πΆππ’ππ‘ππ¦π+ ππππππ‘) (3)
in which β is the cumulative distribution function of standard normal distribution. CDSINIT is an
indicator variable that has a value of one in and after CDS trading initiation, and zero otherwise.
π is a vector of firm-level characteristics that are used to predict the inception of CDS trading. Following Chang et al. (2019), I include all controls into vector π to mitigate the concern that the
determinants of CSR performance may also be factors driving CDS trading initiation. Besides,
following Subrahmanyam et al. (2014), I include the ratio of working capital to total assets and
return on assets as well. Furthermore, I include Fama-French 48 industry classification to isolate
industry fixed effects on CSR performance. I also include country- and year-fixed effects into my
model to address country differential and aggregate time trends effects on CSR performance.
Following Ashcraft and Santos (2009), I use firm-year observations of CDS firms until the
beginning of CDS trading, i.e., excluding CDS firm-year observations in post-CDS-initiation
periods. I combine this traded CDS subsample with all firm-year observations in which firms are
never traded in CDS markets (i.e., non-CDS firms) to construct my whole probit sample and use
it to estimate equation (3). Table 3.4 reports the probit regression results. The model (3) predicts
the onset of CDS trading reasonably well, as evidenced by the high concordant percentage (92.2%)
and pseudo-R2 (35.7%). These statistics are comparable to previous studies. For example, the
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in Martin and Roychowdhury (2015). The coefficients of predictors are in line with the extant
literature (Subrahmanyam et al., 2014; Martin and Roychowdhury, 2015). For instance, larger
firms, firms with high leverage, and more profitable firms attract more attention from CDS market
participants. The coefficient of Governance is positive and significant at the 10% level, suggesting
that firms with good governance are likely to have CDS trading originated in the sample period.
<Insert Table 3.4 about here>
Next, I use the estimates of equation (3) to generate control firms for each CDS firm by comparing
the computed propensity of CDS initiation. Specifically, I compare the estimated likelihood of
CDS initiation of non-CDS firms to that of CDS firms in the year prior to the CDS trading initiation.
I follow Subrahmanyam et al. (2014) to produce three matched samples using different matching
criteria to further verify my results and counter the limitations of propensity score matching
methodology39: (1) the single non-CDS firm has the same Fama-French 48 industry as the CDS
firm and has the closest propensity score to the CDS firm, (2) besides conditions of (1), the non-
CDS firm and CDS firm come from the same country, (3) the two non-CDS firms have the same
CDS firmβs Fama-French 48 industry and have the closest propensity score to the CDS firms.
Moreover, I require the distance of mean propensity scores between CDS and non-CDS samples
not to be statistically significant at the 10% level. I employ Martin and Roychowdhuryβs (2015)
approach to allow a non-CDS firm to match multiple CDS firms. However, the same non-CDS
firm can go into the control sample only once for each year. This way, I have unique firm-year
observations throughout my samples even though a non-CDS firm may serve as a control for
several CDS firms.
39 For example, the propensity score matching method is based on the premise that the control unit is independent of
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I tabulate the firmsβ characteristics of the control-treated sample before the year of CDS trading
initiation in Table 3.5. For brevity, I only present the statistical results based on the matching
criteria (1), which require the closest matched non-CDS firm to have the same Fama-French 48
industry classification as the one of CDS firm. Panel A compares the E&S performances of
matched non-CDS and CDS firms, while Panel B assesses the thirteen firm characteristics and
logit of propensity scores for both samples. In Panel A, I observe that all E&S scores are
statistically the same for CDS and matched non-CDS samples. In Panel B, as shown, CAPEX is
the only firm-level characteristic that is statistically significantly different between the control and
treated samples. The high CAPEX suggests that CDS firms have higher capital intensity than non-
CDS firms. Except for this firm characteristic, CDS firms statistically exhibit the same
characteristics with the non-CDS firms prior to the initiation of CDS trading. These results suggest
that these firm-level CSR determinants documented in extant CSR literature are unlikely the
sources of differences in CSR performance after the inception of CDS trading.
<Insert Table 3.5 about here>