Processus d’audit | Informations privilégiées et transactions privées

Our paper examines insider trading in conjunction with the audit process. Audit reports—and the requirement that public companies file audited financial statements—are a cornerstone of modern financial reporting. While it is generally accepted that financial statement audits mitigate agency conflicts, managers and directors (hereafter “corporate insiders”) are typically aware of the contents of the audit report well in advance of the general public. Thus, although a key purpose of financial statement audits is to protect shareholders, an unintended consequence of the audit process is that it endows corporate insiders with a temporary information advantage. In this study, we examine whether corporate insiders exploit this advantage for personal gain and trade based on private information about audit findings.

The audit process represents a negotiation between the external auditor, management, and the board of directors. A typical audit entails planning and interim procedures during the year, year-end fieldwork around the earnings announcement, and culminates with the preparation of the final audit report. Throughout the audit process, the auditor is in frequent contact with management and the board, and provides continuous updates regarding preliminary findings, audit adjustments, and potential modifications to a standard unqualified audit report. The auditor formally briefs the board on the contents of the final report close to the date that the audit is finalized, or “audit report date” (PCAOB AS 1301). Importantly, this date is not known to the public until the audit findings are subsequently disclosed in the firm’s 10-K filing. Thus, by the very nature of the audit process, corporate insiders will be in possession of material non-public information related to audit findings prior to the 10-K filing.

We examine whether corporate insiders trade based on private information about audit findings using a standard short-window event study around the audit report date. The audit report date signifies the end of the audit, and serves as a reasonable proxy for the latest possible date at which corporate insiders are aware of the final audit findings (PCAOB AS 1301, 3110). Our tests focus on a subset of firms where the audit report date occurs after the earnings announcement and more than ten days prior to the 10-K filing. We focus on audit report dates after the earnings announcement in order to cleanly separate insider trading in conjunction with the audit report from insider trading in conjunction with the earnings announcement. We focus on audit report dates more than ten days prior to the 10-K to ensure insiders’ have the opportunity to trade prior to the public disclosure of the audit findings.

By examining insider trading in a tight window around the audit report date, our event study tests mitigate concerns that our results are attributable to either (a) the audit findings themselves being influenced by insider trading, or (b) omitted firm characteristics correlated with the audit findings. Evidence of a change in insider trading activity in a short window around the audit report date—when audit findings are known to insiders but not to the market—suggests insiders are trading based on private information about the contents of the audit report itself.

We find a pronounced spike in insider trading volume around the audit report date, and that audit reports containing a modified opinion trigger intense insider selling. Highlighting the non-public nature of the audit findings on the audit report date, we find no evidence of a capital market reaction on this date. The presence of significant insider trading activity, coupled with the absence of a capital market reaction, confirms that—in our sample—the audit report date represents a significant internal, non-public, information event.

We conduct an extensive battery of sensitivity tests. For example, we repeat our tests focusing exclusively on within firm-quarter variation in insider trading. To the extent that an omitted variable does not vary within a given firm-quarter (e.g., within Firm A’s 2009-Q4), this analysis controls for the omitted variable (e.g., quarterly performance, governance, growth opportunities, audit quality, reporting complexity, etc.). Focusing exclusively on the timing of trades within the firm-quarter, we continue to find that modified audit opinions trigger intense insider selling around the audit report. Although we cannot definitively rule out the possibility of a correlated omitted variable, we view this as highly unlikely—to explain these results, an omitted variable would have to (i) vary with the timing of insider trades within a given firm-quarter, (ii) vary with the timing of the audit report date within the firm-quarter, and (iii) vary with the audit opinion.

Collectively, our results are consistent with corporate insiders trading based on private information about audit findings. The results suggest the audit process provides insiders with a temporary information advantage, and that insiders opportunistically time their trades to exploit this advantage.

Our research question and findings should be of interest to academics, practitioners, and regulators. With respect to academics, our study extends a long line of auditing research. Our results provide novel evidence that corporate insiders exploit features of the audit process for personal gain. In this regard, our findings suggest a more nuanced understanding of the audit process and the extent to which it protects shareholders and mitigates agency conflicts.

With respect to practitioners—specifically boards and legal counsel—our findings underscore the need for meaningful insider trading policies that effectively limit the key personnel to trade prior to the public disclosure of the audit findings. For example, most firms have insider trading policies that restrict trading around the earnings announcement, but nonetheless allow trading in the intervening period between the earnings announcement and the public disclosure of the audit findings (e.g., Jagolinzer, Larcker, and Taylor, 2011). Boards might want to consider restricting the trade of all officers and directors involved with the audit until the audit findings are publicly disclosed.

With respect to regulators, the Securities and Exchange Commission (SEC) and Public Company Audit Oversight Board (PCAOB) are charged with protecting the interests of individual investors. Consequently, empirical evidence on how audits affect insider trading represents an important consideration in ongoing deliberations on auditing standards and auditing procedures. Our evidence highlights a potentially unintended consequence of audit standards aimed at improving the informativeness of audit reports—as the audit report becomes more informative, the incentives for insiders to front-run the report also increase. Our findings are particularly salient in the context of the new auditing standard that takes effect in fiscal 2019 (PCAOB-2017-01) and changes the audit report from a standardized opinion to one that includes detailed engagement-specific disclosures. We encourage auditors, boards, and regulators to scrutinize insider trades placed in conjunction with corporate audits.

The complete paper is available here.

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Daniel Taylor*est professeur associé à la Wharton School of the University of Pennsylvania.