When we talk about key rate duration, does the RATE refer to YTM or spot rate?
Say for example, the 5 year key rate duration for a 10 year bond is 6. Bond price will fall by 6% due to:
- 1% increase in 5 year benchmark YTM
or
- 1% increase in 5 year benchmark spot rate?
The rate of key rate duration is par yield or bond yield?
I’m not sure I understand your question.
Key rate duration is computed by changing a single par rate, leaving all other par rates unchanged.
It has some unusual implications for the spot curve; therefore, it has some unusual implications for bond prices.
I wrote an article on key rate duration that covers it quite clearly: http://financialexamhelp123.com/key-rate-duration/. This is one of the free sample articles on my website.