I-spread为什么反应credit risk？

同学你好，

麻烦仔细阅读以下一句

I-spread stands for interpolated spread. It is the difference between yield on a bond and the swap rate, i.e. the interest rate applicable to the fixed leg in the floating-for-fixed interest rate swap. The difference between yield on a bond and a benchmark curve such as LIBOR is useful in assessing credit risk of different bonds. Higher i-spread means higher credit risk.

特别是这一句“The difference between yield on a bond and a benchmark curve such as LIBOR i”