A graph showing the relationship at a selected point in time between the available maturities of a security or similar securities with essentially identical credit risk and the yields that can be earned for each available maturity. A graphical depiction of the term structure of interest rates at any given point in time. Yield curves may be constructed for different instruments such asTreasury securities, AAA-rated municipal bonds, A-rated corporate bonds, etc. Even within the field of Treasury securities, yield curves are constructed from many different types of Treasury rates. When a yield curve is constructed by calculating the coupon rates necessary for the Treasury obligations of various maturities to be priced at par, it is called a par yield curve. When a yield curve is constructed using currently prevailing rates for instruments available for cash delivery, it is called the spot curve. When a yield curve is constructed using currently prevailing rates for instruments to be delivered at future dates, it is called the forward yield curve. When a yield curve is calculated using currently prevailing rates for interestbearing Treasuriy securities, it may be referred to as a coupon curve. When a yield curve is calculated using currently prevailing yields for zero coupon instruments, it is called the zero coupon curve.