What is Treasury index?
An index that is used to determine interest rate changes for certain adjustable rate mortgage (ARM) instruments. The index is based on the results of auctions that the U.S. Treasury holds for its Treasury bills and securities. Or it can be derived from the U.S. Treasury's daily yield curve, which is based on the closing market bid yields on actively traded Treasury securities in the over-the-counter market. See adjustable-rate mortgage ("ARM").