We investigate the impact of the Sarbanes–Oxley (SOX) Act on the cost of debt through its effect on the reliability of financial reporting. Using Credit Default Swap (CDS) spreads and a structural CDS pricing model, we calibrate a firm-level corporate opacity parameter in the pre- and post-SOX periods. Our analysis shows that corporate opacity and the cost of debt decrease significantly after SOX. The median firm in our sample experiences an 18bp reduction on its five-year CDS spread as a result of lower opacity following SOX, amounting to total annual savings of $ 844million for the 252 firms in our sample. Furthermore, the reduction in opacity tends to be larger for firms that in the pre-SOX period have lower accrual quality, less conservative earnings, lower number of independent directors, lower S& P Transparency and Disclosure ratings, and are more likely to benefit from SOX-compliance according to Chhaochharia and Grinstein’s (2007) criteria.

Investor overconfidence, characterized by an excessive belief in the ability to generate superior portfolio returns, is a widely studied behavioral bias. This paper investigates the mechanisms underlying overconfidence using a Bayesian model that incorporates two features: biased prior beliefs, which imply overconfidence even before investors engage in the stock market, and biased learning, where investors overemphasize instances of outperforming the market. Empirical analysis supports the hypothesis that biased learning contributes to overconfidence, but only in the early years of investor tenure. Although overconfidence decreases with investment experience, we find that it is a widespread and persistent behavioral trait.