NO.PZ2020011303000223
问题如下:
What is the effective duration and convexity of a three-year Treasury bond with a face value of 1 million and a coupon of 4% when the term structure is flat at 5%? Express interest rates in decimals and consider five-basis-point changes.
解释:
The value of the bond is 97.245937. When there is five-basis-point increase in all rates so that the term structure is flat at 5.05%, the value falls by 0.135287 to 97.110650. When there is a five-basis-point decrease in all rates so that the term structure is flat at 4.95%, the value rises by 0.135514 to 97.381452. The duration is
0.5×(0.135287+0.135514)/(97.245937×0.0005)=2.784703
The convexity is
(97.110650+ 97.381452-2×97.245937)/(97.245937× 0.00052)=9.35
Note that even more decimal places than those indicated is necessary to provide
this estimate of convexity.
题目问:3年期的treasury bond,面值=1m,coupon rate=4%,利率=5%,利率的期限结构是flat的。求这个债券的effective duration和convexity。利率的变动幅度是5bp。
treasury bond一般每半年付息一次。
首先利用计算器求债券的价格V0:PMT=100*4%/2=20,FV=100,I/Y=5%/2=2.5%,N=3*2=6,得PV=97.245937
利率上升5bp时,债券价格V-:PMT=100*4%/2=20,FV=100,I/Y=5.05%/2=2.525%,N=3*2=6,得PV=97.110650
价格下降0.135287
利率下降5bp时,债券价格V+:PMT=100*4%/2=20,FV=100,I/Y=4.95%/2=2.475%,N=3*2=6,得PV=97.381452
价格上升0.135514
duration=0.5*(价格上升幅度+价格下降幅度)/(V0*2)
0.5×(0.135287+0.135514)/(97.245937×0.0005)=2.784703
convexity=(V+ + V- -2*V0)/(V0*利率变动^2)
=(97.110650+ 97.381452-2×97.245937)/(97.245937× 0.00052)=9.35
请问,用PMT20,FV100,用2,5利率,六期这几个数字反复按计算器都等于196。实在不知错在哪了?都是这么按的,烦请示范一下,感谢