Lehman Aggregate Bond Index An index used by bond funds as a benchmark to measure their relative performance. The index includes government securities, mortgage-backed securities, asset-backed securities and corporate securities to simulate the universe of bonds in the market. The maturities of the bonds in the index are more than one year. Investopedia Says: The index constructed by Lehman Brothers is considered to be the best total market bond index, as it is used by more than 90% of investors in the United States. Along with the aggregate index, Lehman also has bond indexes tailored to European and Asian investors. This index cannot be purchased, but it is tracked by bond index funds; there also has an iShare exchanged-traded fund (ETF) that tracks the index. Related Terms: Asset-Backed Security - ABS Bond Core Plus Corporate Bond Government Security Index Index Fund iShares Lehman Brothers Mortgage-Backed Securities Index Mortgage Backed Securities - MBS |