Carbon emissions trading system and corporate tax avoidance

We selected companies listed on the Shanghai and Shenzhen stock exchanges from 2008 to 2020 as our initial sample. The list of companies participating in the ETS was obtained from the official websites of local Ecological Environment Bureaus and Development and Reform Commissions. Financial data were sourced from the China Stock Market & Accounting Research Database. The samples were processed as follows: (1) samples with missing data were excluded; (2) samples from the financial industry were excluded because of the special calculation and characteristics of financial statements; (3) samples from state-owned enterprises were excluded owing to their specific nature for tax avoidance; (4) companies identified as having special treatment were excluded to reduce the influence of outliers; and (5) winsorization was performed on continuous variables, truncating values at the 1st and 99th percentiles to eliminate the impact of outliers.

Between 2013 and 2014, China launched pilot ETS in Shenzhen, Beijing, Shanghai, Tianjin, Guangdong, Hubei, and Chongqing. In 2016, Fujian and Sichuan also joined the pilot program. To define the treatment group, we referred to the list of companies covered by ETS published by local regulatory authorities, which clearly identifies companies joining the ETS. Companies not included in these lists were categorized as the control group. To address potential endogeneity issues, this study employed the propensity score matching (PSM) method to select the sample. Referring to Chen et al. (2018) and Chen et al. (2022), this study considered companies who are in pilot ETS as the treatment group (Treat = 1) and non-pilot companies as the control group (Treat = 0). Specifically, this study used the following variables to conduct 1:1 nearest neighbor matching without replacement on the sample: static non-systematic risk (ALTZ), asset return volatility (EV), systematic risk (BETA), leverage ratio (Lev), fixed asset ratio (PPE), intangible asset ratio (Intang), return on investment (ROI), research and development expenses (RND), whether the chairman and CEO are the same person (Dual), the shareholding proportion of the largest shareholder (Top1), firm size (Size), return on assets (ROA), book-to-market ratio (Bm), audit opinion (Audit), whether the firm is in a loss in previous year (Loss), provincial-level EPU (EPU), and proportion of executives with political connections (PC).

Finally, 2,691 matched pairs of sample observations were obtained.

本研究所选取的初始样本为2008年至2020年间在上海证券交易所和深圳证券交易所上市的公司。参与ETS（碳排放交易体系）的企业名单来源于地方生态环境局和发展改革委员会的官方网站。财务数据来源于中国股票市场与会计研究数据库。样本处理过程如下：（1）剔除数据缺失的样本；（2）因金融行业财务报表的特殊计算和特性，排除金融行业样本；（3）鉴于国有企业避税的特殊性质，排除国有企业样本；（4）为减少异常值的影响，排除获得特殊待遇的公司样本；（5）对连续变量进行Winsorization处理，截断1%和99%分位数处的值，以消除异常值的影响。在2013年至2014年间，中国在北京、上海、深圳、天津、广东、湖北和重庆等地启动了ETS试点项目。2016年，福建和四川也加入了试点项目。为了界定处理组，本研究参考了地方监管机构发布的ETS覆盖企业名单，该名单明确标识了加入ETS的企业。未包含在这些名单中的公司被归类为对照组。为解决潜在的内生性问题，本研究采用了倾向得分匹配（PSM）方法来选择样本。参照Chen等（2018）和Chen等（2022）的研究，本研究将试点ETS中的企业视为处理组（Treat = 1），非试点企业视为对照组（Treat = 0）。具体而言，本研究使用以下变量在样本上进行1:1最近邻匹配，不进行重复匹配：静态非系统性风险（ALTZ）、资产回报波动性（EV）、系统性风险（BETA）、杠杆率（Lev）、固定资产比率（PPE）、无形资产比率（Intang）、投资回报率（ROI）、研发费用（RND）、董事长与CEO是否为同一人（Dual）、最大股东持股比例（Top1）、公司规模（Size）、资产回报率（ROA）、账面市值比（Bm）、审计意见（Audit）、公司是否在上一年度亏损（Loss）、省级EPU（EPU）、具有政治关联的高管比例（PC）。最终，获得了2,691对匹配的样本观测值。