which LT debt to use in Bond +Risk premium

CFA Level II
#1

In the textbooks there is an example on IBM.

30 year T bond YTM: 3.7%

IBM 2042 YTM: 4.43%

Risk Premium 2.75%

Answer is 4.43+2.75 = 7.18

Just curious why we are using IBM debt and not government debt which surely would have a better rating.

Thanks

#2

If you evaluatig a corporation bond similar to IBM, I would use IBM’s bond yield, not the treasury’s. This looks like matrix pricing, or not?