Definition - What does Treasury Index mean?
The treasury index is an ongoing compilation of the curve on the US Treasury. It is the amount of value held in bonds and in the treasury at any point in time. The rate of interest that a lender offers a borrower is related to the treasury index because the rate that the lender borrows at is tied to this number. By law, a lender cannot tie a rate to the index that falls outside of the determined rules.
Justipedia explains Treasury Index
There are stocks and bonds that are tied to the treasury index for sale to individual investors while other investors bet or invest against the belief that the index will change within a certain parameter, either higher or lower than it is at present. Any illegal trading of stocks or bonds can have a negative impact on the treasury index and is one of the reasons why such trades are illegal.