NO.PZ2021120102000010
问题如下:
Which of the following statements best describes empirical duration?
选项:
A.A common way to calculate a bond’s empirical duration is to run a
regression of its price returns on changes in a benchmark interest rate.
A bond’s empirical duration tends to be larger than its effective duration.
The price sensitivity of high-yield bonds to interest rate changes is typically
higher than that of investment-grade bonds
解释:
A is correct. A bond’s empirical duration is often estimated by running a regression of its price returns on changes in a benchmark interest rate.
empirical duration是观察到的债券价格对基准利率变动的敏感程度,effecive duration是理论上计算的债券价格对基准利率变动的敏感程度。empirical duration小于effective duration,尤其是HYB,二者的差异更大,这是一个实证检验观察到的一个现象。具体原因如下:
由于yc=yb+spread且yb与credit spread有负相关关系(理论基础是△yb>0表明经济好,此时,投资者对市场未来看好,对债券credit premium要求较低,因此credit spread变小),所以△yb>0,credit spread下降,也就是△spread<0,进而△yc<△yb,抵消作用就是credit spread与基准利率的负相关导致的。
假设△yb=1%,那么根据上面的分析,△yc<1%,△yc引起的△%P<△yb引起的△%P,前者是empirical duration,后者是effective duration,所以,empirical duration 通常要比 effective duration小。
相比于IG,因为HYB的credit spread与yb负相关关系更大,所以相对于IG,HYB的empirical duration比effective duration小的更多。
我的思路也是如此,但是发亮老师的讲解,effective duartion和emprical duration都是基于benchmark计算的,是类似概念,但不是analytical duration(假设yb和spread独立变化),所以想问下,那么B错在哪?谢谢