This study investigates the investment constraints and trading behavior of US public pension funds in bond markets. While they are traditionally viewed as long-term investors, novel data on liability duration and security holdings reveals that these funds exhibit a significant duration mismatch and a tilt toward short-term corporate bonds despite long-term liabilities. To explain this, I examine the role of another investment constraint – target funding ratios. The more constrained they are, the more actively they invest in short-term and high-yield bonds, implying a reaching-for-rating strategy than reaching for maturity. I further explore the main drivers of their persistent underfunded status.