<p>This study investigates the influence of accounting reporting complexity on corporate risk assessment. We hypothesize that increased accounting complexity in financial reporting leads to higher information risk, which negatively influences firms’ credit ratings. Using eXtensible Business Reporting Language (XBRL) as a proxy for accounting reporting complexity, we find that the increased use of extended XBRL tags is negatively associated with long-term firms’ credit ratings. We also find that the negative association between the extended XBRL tags and credit ratings is more pronounced among firms with higher default risk and firms facing greater earnings volatility. Our results are robust to alternative resgresison specifications and our findings remain consistent when we apply propensity score matching and entropy balance techniques to alleviate endogeneity concern. Overall, our results suggest that credit rating agencies recognize accounting reporting complexity as a non-financial determinant of creditworthiness, providing implications for financial reporting practices and regulatory oversight of XBRL usage.</p>