What was the spread (margin) above a comparable maturity Treasury bond at the time of the issue? [Spread means Credit spread or default spread or yield spread (p. 177 of textbook). It is the difference between the yield to maturity (YTM) on your bond and the YTM on a Treasury note or bond of similar maturity. It is an indicator of default risk.] [Source: finra.org] . This is for Boeing issue date was 9/15/1991. Maturity Date 9/15/2031 YTM is 3.802