The index of US government bonds with a 6-month maturity (6-month notes or in general 6-month treasuries). It measures the generic government 6-month yield for US issues of treasuries and provides the benchmark for various relatively short-term fixed-income instruments. It is typically used to find out yield spreads for a host of fixed-income instruments with 6-month maturities.

Generally speaking, the U.S. Treasury bill 3-6 month index (USGG6M) is designed to reflect/ gauge the performance of U.S. Treasury bills with maturities ranging from 3 to 6 months.