An interest rate swap in which a swap rate is exchanged for either a fixed rate or a floating rate on each payment date. The floating rate resets periodically at or with reference to LIBOR or any floating reference index rate. The fixed rate is reset periodically with regard to a regularly available fixed maturity rate. The constant maturity rate represents the yield on a security whose maturity goes beyond the reset period. That exposes the parties to this swap to any potential changes in longer term market rates. The most widely-used constant maturity rates are sovereign rates (yields on 2- 5 year government debt).