The index of US government bonds with a 9-month maturity (9-month notes or in general 9-month treasuries). It measures the generic government 9-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 9-month maturities.

Generally speaking, the U.S. Treasury bill 6-9 month index (USGG9M) is designed to reflect/ gauge the performance of U.S. Treasury bills with maturities ranging from more than 6 months to 9 months.