Book excerpt: This thesis consists of three chapters on institutional investors in bond market. Chapter 1 examines duration hedging behavior in corporate bond market by studying investment decisions of life insurance companies, the largest institutional investors in this market. I find that life insurers are tilting their corporate bond portfolios towards bonds with higher duration as interest rates decrease to historical lows since the 2008 financial crisis. This hunt-for-duration behavior is due to life insurers' interest rate risk hedging to ensure better duration matching between their assets and liabilities. I further show that hunt-for-duration by life insurers can drive overpricing of corporate bonds when negative monetary policy surprises hit. Chapter 2 investigates how the risk-based capital (RBC) reform in insurance industry initiated in year 1993 affects life insurers' investment behavior in corporate bonds, and how RBC-induced distortion in insurers' investment practices could have an impact on credit allocation, and ultimately real investment in the economy. Following the reform, I observe that insurers tilt their portfolios towards the lowest rated corporate bonds within a bond risk category defined by the RBC rule. Through shifting insurers' bond demand, I find that the RBC reform changes the credit supply conditions to a particular group of firms: those that have credit ratings barely fitting into a low-risk category and belong to industries where insurers hold more corporate bonds before the reform. Furthermore, I find that these firms take advantage of the more favorable credit allocation conditions to increase investment and employment after the reform. These results highlight a channel through which regulatory reform in insurance industry can bear real consequences.Chapter 3 studies whether life insurers rebalance their bond portfolios during Quantitative Easing (QE) programs initiated by the Federal Reserve (Fed) since the 2008 financial crisis. I find that life insurers sell QE securities and replace them with corporate bonds over certain QE periods. Moreover, life insurers rebalance toward corporate bonds in the lowest rating tier within a risk category defined by the RBC rule under which insurers are regulated. Overall, these findings show that QE's portfolio rebalancing channel can work through the life insurance sector.