감사의견 구매 목적의 감사인 교체와 감사품질 하락

Outsiders suspect that clients seem to change or retain auditors in a way to receive clean audit opinion from auditors. The auditor change for opinion shopping purpose implies that clients change auditors from the one who is likely to issue non-clean opinion to the other who is likely to issue clean opinion more frequently. Regulators have had great concern on the possibility of opinion shopping behavior because it will affect auditor independence, which leads to impairment in audit quality. For example, MacDonald Commission (1987), Cadbury Committee (1992), European Commission (2010) explicitly express the concern on that issue. In response, in the U.S., Sarbanes-Oxley Act requires Government Accounting Office to develop the ways to protect auditor independence from the threat by audit clients to change auditors if a clean audit opinion is not given. However, before Lennox(2000), there is no clear empirical evidence for the existence of auditor change for opinion shopping purpose. Prior studies only document the evidence that clients tend to change auditors more frequently after they receive non-clean audit opinion. However, they do not find any significant changes in the audit opinion even after such auditor changes (Chow and Rice 1982; Geiger et al. 1998; Krishnan and Stephens 1995; Park and Nam 2014). Thus, the prior studies have concluded that opinion shopping behavior is futile, even though it seems to exist. Relatedly, in the domestic research, Park and Nam(2014) also covers the issue of plausible opinion shopping behavior using Korean non-listed firms. However, like prior studies before Lennox(2000), they just show that client tend to switch auditor especially to a non-Big 4 auditor after receiving non-clean opinion from the incumbent auditor. They do not provide any evidence that such auditor changes lead to the improved auditor opinion. This implies that with their findings, we cannot be sure whether such auditor changes are intended for opinion shopping or not, and whether such auditor changes are successful in a sense of opinion shopping purpose. Even though they show that after the auditor switches, audit quality measured by discretionary accruals is poor, these results have limitations in that the auditor change is separated only based on prior audit opinion, not on the intention of clients for opinion shopping purpose. Regarding the failure of prior studies in finding opinion shopping behavior, Lennox (2000) points out that we cannot identify the opinion shopping behavior just comparing prior nonclean opinion to current clean opinion after auditor switch because if the clients did not change auditors, they would have received non-clean opinions more frequently. And he develops a new way to test the existence of audit opinion shopping. He estimates the probabilities of a client to receive a non-clean opinion from the incumbent auditor and from a new auditor, and compares the two probabilities. He views that if clients change auditors when the former is higher than the latter, it can be the evidence of opinion shopping. Using the U.K. data, he shows that clients prefer changing auditors when the clients are more likely to receive clean audit opinions from new auditors than from incumbent auditors. In contrast, clients tend to stick to incumbent auditors when they are likely to receive clean opinions more frequently from incumbent auditors than from new auditors. Using 70,040 firm-year observations of Korean non-listed firms collected over the period from 2006 to 2013, we first replicate Lennox (2000). We restrict our samples to non-listed firms because most listed firms in Korea receive clean opinions. Among the total sample, 9,528 observations change auditors while the remaining 60,512 observations retain their incumbent auditors. Our empirical findings reveal that the Korean non-listed firms tend to engage in opinion shopping behavior. When we apply the methodology of Lennox(2000), among our auditor change samples, 1,171 changes are classified as those for opinion shopping purpose while the remaining changes are classified as those for other purposes. Second, we investigate whether audit quality changes after auditor changes for opinion shopping purpose. We measure audit quality using the absolute value of performance-matched discretionary accruals(Kothari et al. 2005). In level analysis, we find that audit quality is poor when auditor change occurs and it is even poorer when the auditor change is intended for opinion shopping, compared with the audit quality when no auditor change occurs. When we consider the different types of auditors in relation to the auditor changes for opinion shopping purpose, we find that the change from a non-Big 4 to another non-Big 4 auditor is related to poor audit quality, while the other types of auditor changes are not. In the change analysis, we document that audit quality deteriorates when clients change auditors for opinion shopping purpose, compared with the audit quality of the same client firm in the previous year(i.e., before the auditor changes). In contrast, audit quality does not deteriorate from that of prior year for the same clients when the auditor changes are intended for other purposes. When we consider different types of auditor changes, we find that only the changes from a non-Big 4 to another non-Big 4 auditor lead to deterioration of audit quality. Unlike the level analysis, we fail to find any significant evidence that audit quality deteriorates for the clients that switch auditors for other purposes than opinion shopping purpose. Our findings are interesting and important in demonstrating the effect of opinion shopping. Regulators need to pay attention to this phenomenon and develop ways to restrict it. Mandatory auditor appointment or investigation by Financial Supervisory Service (an organization equivalent to Securities and Exchange Commission in the U.S.) can be those examples. Auditors also need to be careful for accepting such clients not to face the unfavorable outcome from poor audit quality. Accepting clients for opinion shopping and resulting poor audit quality can potentially lead to audit failure in the future. Investors and other interested parties also need to pay attention to the poor audit quality in their respective decision-makings.