This paper examines the relation between portfolio concentration and investment performance in corporate bond mutual funds. Using detailed holdings data, we construct portfolio concentration measures at the firm, industry, and credit rating levels. We find that portfolio concentration is significantly positively related to expected abnormal returns of corporate bond funds, and this relation is mainly driven by investment-grade funds. High-yield funds, however, do not exhibit such a relation, possibly due to the erosion of the value of portfolio concentration by liquidity costs. In support of this conjecture, we document that the concentration-performance relation is less pronounced among funds with higher sensitivities to market-wide illiquidity innovations and during periods of bond market illiquidity shocks and fund-level net money outflows. Finally, we show that more concentrated funds demonstrate stronger performance persistence, and investors appear to consider portfolio concentration in making investment decisions.

We investigate whether and how a “critical audit matter” (CAM) disclosure affects managers' real operating decisions in two contexts (issuing a loan that decreases versus increases the average risk profile of loan portfolios, or choosing to hedge versus speculate on commodity risk). We expect that a CAM disclosure increases disclosure costs and implies expanded auditor support for both types of activities, but we expect implied auditor support to be valued more highly for risk-increasing than for risk-decreasing activities. As a result, we predict that a CAM disclosure decreases managers' risk-decreasing activities (due to increased disclosure costs) more than managers' risk-increasing activities (as the implied auditor support counteracts the increased disclosure costs). We find evidence consistent with our prediction across multiple experiments. Our study sheds light on the unintended consequences of a CAM disclosure and provides insight to relevant parties as the new standard goes into effect.

Informed by Perceptual Deterrence Theory, we conduct multiple experiments to investigate when and how auditor actions can help deter manager opportunism. In Study 1A, we find that managers are less likely to use real earnings management (REM) when they expect auditors to both increase scrutiny and communicate their observations to the board. However, this effect occurs only when managers' operational decisions are inconsistent (versus consistent) with peer behavior. Study 1B findings suggest that increased auditor scrutiny alone (without auditor-board communication) is not likely to deter REM. In Study 2, we find that increased auditor scrutiny with communication to the board effectively deters both accruals-based earnings management (AEM) and REM, reducing the total level of manager opportunism. However, without communication, increased auditor scrutiny deters AEM, but also induces more REM. Our findings highlight the importance of auditor-board communication and demonstrate how auditor actions can contribute to the deterrence of manager opportunism. Data Availability: Contact the authors.