Butterfly Shift

Butterfly shift is a term in finance for a change in the yield curve for bonds, named after the shape of the yield curve, which looks like a butterfly flapping its wings. Such a curve is created when yields on short-term and long term bonds are the same but on medium-term bonds does not. Such a shift is said to be positive when yields on short and long term bonds are higher than the yield on medium-term bonds, and is said to be negative when short and long term yields are lower than the medium-term yield.