摘要：“沪深港通”作为资本市场高水平开放的重要实践，是中国推进制度型开放在金融领域的关键探索。本文以2009—2022年中国沪深A股上市公司为研究样本，以“沪深港通”标的名单的发布作为准自然实验场景，构建多期双重差分模型，实证检验资本市场开放对企业ESG漂绿的影响。研究结果表明，资本市场开放对企业ESG漂绿具有显著的抑制作用。机制检验结果显示，信息效应、治理效应及资源效应是资本市场开放抑制企业ESG漂绿的重要机制，具体表现为缓解企业信息不对称、降低企业代理成本、减轻企业融资约束。异质性检验结果显示，在环境规制较严格、市场竞争较激烈的样本企业中，资本市场开放对企业ESG漂绿的抑制作用更为显著。这意味着较强的环境规制与较充分的市场竞争有助于强化资本市场开放对企业ESG漂绿的治理效能。经济后果检验表明，资本市场开放对企业ESG漂绿的治理作用，能够进一步提升企业全要素生产率，推动企业实现高质量发展。基于上述结论，本文提出以下建议：第一，在政府与监管层面，应推动资本市场高水平开放与环境规制协同发力，完善ESG信息披露制度，建立跨部门联动监管机制，提高虚假披露的违规成本；第二，在市场与交易所层面，应细化ESG信息披露标准，强化定量披露要求，通过公开透明的信息反馈增强市场声誉约束；第三，在企业层面，应建立规范的ESG数据管理与内部控制体系，将资本市场开放带来的融资改善与外部监督压力转化为推动绿色技术创新与治理优化的动力，以真实可持续的ESG绩效支撑企业高质量发展。

Abstract: As a pivotal practice of high-level capital market opening, the Shanghai-Hong Kong Stock Connect and Shenzhen-Hong Kong Stock Connect programs represent a key institutional innovation in China's financial opening-up process. Using a sample of Chinese A-share listed firms from 2009 to 2022, this study exploits firms' inclusion in the Stock Connect programs as a quasi-natural experiment and employs a multi-period difference-in-differences model to empirically examine the impact of capital market opening on corporate ESG greenwashing. The results indicate that capital market opening significantly curbs corporate ESG greenwashing through three underlying mechanisms: an information effect by alleviating information asymmetry, a governance effect by reducing agency costs, and a resource effect by easing financing constraints. Heterogeneity analyses reveal that this inhibitory effect is more pronounced in firms subject to stricter environmental regulations and operating in more competitive markets, suggesting that robust environmental oversight and intense market competition reinforce the governance role of capital market opening in mitigating ESG greenwashing. Further analyses of economic consequences demonstrate that the restraining effect of capital market opening on ESG greenwashing contributes to improvements in firms' total factor productivity, thereby promoting high-quality development. This study not only extends the literature on the economic consequences of capital market opening and the determinants of corporate ESG greenwashing but also provides policy implications for steadily advancing high-level capital market opening, strengthening environmental regulation, and fostering market competition to curb ESG greenwashing.