This paper presents the first comprehensive study on the determinants of public pension fund investment risk and reports several new important findings. Unlike private pension plans, public funds undertake more risk if they are underfunded and have lower investment returns in the previous years, consistent with the risk transfer hypothesis. Furthermore, pension funds in states facing fiscal constraints allocate more assets to equity and have higher betas. There also appears to be a herding effect in that CalPERS equity allocation or beta is mimicked by other pension funds. Finally, our results suggest that government accounting standards strongly affect pension fund risk, as higher return assumptions (used to discount pension liabilities) are associated with higher equity allocation and portfolio beta.

We examine the effect of discount rate changes on stock market returns, volatility, and trading volume using intraday data. Equity returns generally respond negatively and significantly to the unexpected announcements; however, the effect of expected changes on equity returns is insignificant. Furthermore, our results indicate that equity prices respond to announcements within the trading period/hour after the information release. An indication of a return reversal is too small to cover the full transaction costs. Unexpected discount rate changes also contribute to higher market volatility although the volatility is short-lived. Similarly, unexpected changes in discount rates induce larger trading volume while expected changes do not. Abnormal trading volume occurs only in period t. Our results also support the notion that unexpected changes in the discount rates impact market returns irrespective of the Federal Reserve operating procedures.