This dissertation investigates the interrelationships between a client's non-GAAP earnings disclosures, financial health (profit and loss status), and the external auditor's assessment of the client's going concern status. This dissertation comprises two essays. Essay 1 examines the informativeness and the quality of non-GAAP earnings disclosures in profit and loss firms separately. Using a large sample of non-GAAP earnings voluntarily disclosed by managers, I find that the informativeness and the quality of non-GAAP earnings vary in firms cross-classified by GAAP loss status and non-GAAP loss status. I also find that loss firms have higher quality non-GAAP exclusions relative to profit firms, although the expenses excluded by both profit and loss firms are associated with firms' future performance. Further, I posit and find that profit firms which voluntarily disclose non-GAAP losses have high-quality exclusions, while other non-GAAP reporting profit firms have low-quality exclusions. Having found that non-GAAP earnings in loss firms is opportunistic to some extent, I next study, in Essay 2, whether auditors understand the implications of low-quality non-GAAP reporting in these firms. Specifically, I examine 1) whether non-GAAP earnings disclosures are associated with the propensity of the auditor's going concern issuance to loss firms, and 2) whether non-GAAP earnings disclosures affect the accuracy of the auditor's going concern assessment. This is important because auditors often conduct audits of loss firms that disclose non-GAAP earnings, and the consequences of issuing wrong audit opinions can be severe. I find that the propensity of the auditor's going concern issuance is negatively associated with the magnitude of expense exclusions in loss firms, after controlling for determinants of going concern opinions that are derived from GAAP earnings. This finding suggests that auditors take into account information embedded in non-GAAP earnings when assessing clients' going concern status. Using bankruptcy outcome as a benchmark, I find that non-GAAP earnings disclosures could increase type II errors in auditors' going concern reporting. I further find that small size auditors and non-specialist auditors are more likely to be misled by non-GAAP reporting when making going concern decisions. In sum, my dissertation furthers our understanding of non-GAAP reporting and its implication for auditors' decision making for issuing going concern opinions.