PPT Slide
Coupon payments are reset periodically according to some reference rate.
reference rate + index spread
e.g. 1-month LIBOR + 100 basis points (positive index spread)
5-year Treasury yield - 90 basis points (negative index yield)
Reference rate can be some financial index
e.g. return on the S & P 500 or non-financial index
e.g. price of a commodity or inflation index
(in 1997, US government begin issuing such bonds)