This dissertation consists of two topics. Chapter 1 explores the relationship between firm transparency and managerial behaviors of the U.S. Property-Casualty (P&C) insurers. Using data between 1996 and 2015, we test whether credit rating agencies (CRAs) provide useful information to monitor insurers’ loss reserve management behaviors as watchdogs. In addition, we investigate how insurers recognize the rating difference given by different CRAs. We find that holding a rating does not necessarily affect insurers’ reserve management behaviors. However, loss reserve estimation tends to be more accurate as more ratings are given to an insurer. Such findings suggest that multiple CRAs stimulate insurers to accurately estimate their reserves through the enhanced monitoring function. We also find a marginal impact of rating difference on an insurer’s loss reserve estimation. Firms with rating difference tend to underestimate their loss reserves. Nevertheless, this does not considerably deteriorate the reserve forecast accuracy. Although the Sarbanes–Oxley Act (SOX) aims at regulating publicly traded firms, it seems to affect over the market. Our empirical results show that insurers’ reserve estimation accuracy is improved after the enactment of the SOX. Moreover, the enactment of SOX alleviates an under-reserving behavior of firms with rating difference. Chapter 2 investigates the derivative practice of the U.S. life insurers. Over the last two decades, derivatives have been used extensively as a risk management tool in the financial market. In the U.S. insurance market, life insurers have accounted for over 95% of total derivative transactions, a proportion much higher than that in other countries. However, there are only a few prior studies examining the practical use of derivatives in the U.S. life insurance market. In addition, several limitations exist in terms of data they used (single-year, outdated, and inaccurate). In this study, we compile accurate derivative transaction data by taking a close look at the underlying asset and the traded market. We then examine the determinants of derivative (swap in particular) participation and the extent of transactions using samples from 2001 to 2015 which includes major events such as the U.S. financial crisis and the Dodd-Frank Act. We find that the determinants of derivative/swap participation are different from those of transaction volumes. We also find that the impact of the financial crisis on derivative usage is very limited in the life insurance market. However, the enactment of the Dodd-Frank Act not only reduces the likelihood of swap participation but also stagnates the growth of the swap transaction volumes, while the total derivative transaction volumes are significantly increased. Such findings indicate that the costs of the new regulation outweigh its benefits, due to the inefficient and inadequate regulatory changes. / Business Administration/Risk Management and Insurance