This study provides evidence that auditors are more likely to issue going concern opinions to client firms that more heavily rely on major customers for sales. We initially find that these results are driven by non-Big 4 auditors, and Big 4 auditors with lower abnormal audit fees, with smaller offices and without industry expertise at the city-level. However, we find that the positive association between greater major customer reliance and going concern opinions issued by non-Big 4 auditors is insensitive to various factors representing the ability of the supplier to retain the major customer. In contrast, Big 4 auditors are more likely to take such factors into account when issuing going concern opinions in the presence of greater major customer reliance, regardless of their level of abnormal audit fees, office size, and industry expertise. Further, we show that Big 4 auditors with lower (higher) abnormal audit fees, with smaller (larger) offices and without (with) industry expertise at the city-level are (are not) associated with the issuance of going concern opinions in the presence of greater major customer reliance when firms avoid bankruptcy (i.e., Type I error). This suggests Big 4 audits that are of higher quality more accurately assess the business risks associated with greater reliance on major customers prior to issuing going concern opinions.