This paper investigates whether the level of customer concentration can moderate the effect of the Sarbanes–Oxley Act of 2002 (SOX) on the earnings management of U.S. corporations. Large customers can act as a mechanism for reducing agency problems by pressuring supplier firms to be more efficient. Large customers may act as certifying agents for a supplier, and they may reduce information asymmetries about the supplier. These two channels suggest that customer concentration may affect corporate earnings management and hence generate heterogeneity in the effects of SOX. This paper documents that SOX has led firms with low customer concentration to reduce accrual-based earnings management more than those with high customer concentration have. The effect of customer concentration is especially pronounced when firms are involved in higher relationship-specific investments. The results are robust to accounting for endogeneity and alternative measures of discretionary accruals and customer concentration.

本文研究了客户集中度是否可以缓和 2002 年萨班斯-奥克斯利法案 (SOX) 对美国公司盈余管理的影响。大客户可以通过迫使供应商提高效率来充当减少代理问题的机制。大客户可以作为供应商的认证代理人，他们可以减少关于供应商的信息不对称。这两个渠道表明，客户集中度可能会影响企业盈余管理，从而在 SOX 的影响中产生异质性。本文记录了 SOX 导致客户集中度低的公司比客户集中度高的公司减少了应计盈余管理。当公司参与较高的特定关系投资时，客户集中度的影响尤其明显。结果对于考虑内生性和可自由支配应计和客户集中度的替代措施是稳健的。