This excerpt taken from the PCG 10-K filed Feb 24, 2009.
SRSP Bond Index Fund seeks to match the returns of the Lehman Brothers Aggregate Bond Index. The Fund invests primarily in government, corporate, mortgage-backed, and asset-backed fixed-income securities. The Fund invests in a well-diversified portfolio that is representative of the broad domestic bond market. The Lehman Brothers Aggregate Bond Index is an unmanaged market-value weighted index of investment-grade, fixed-rate debt issues, including government, corporate, asset-backed, and mortgage-backed securities, with maturities of one year or more. The Fund is managed by State Street Global Advisors (SSgA).