问题如下图：
选项：
A. 
B. 
C. 
老师我有点混淆了，2年后卖公司债券不是应该先算 f(2 2)吗，求出价格，为什么两年后的债券价格能用t=0时刻的利率直接取算的
解释：
包包_品职助教 · 2019年03月08日
同学你好，这个题目有点没说清楚利率是稳定的，不过由于S同学采用的是riding the yield curve策略，而该策略应用的前提就是收益率曲线不变，所以两年后的两年期利率就等于现在的两年期利率。
f(2 2)=(1+s4)^4/ (1+s2)，这个公式是用forward rate model用来计算forward rate ，这样计算出来的forward rate 其实是一个breakeven rate，即直接投四年和先投两年再投两年这两种投资方法对投资者来说是一样的，实际上第二种方案是有再投资风险的。
每天都想出坑的铁头娃 · 2019年03月08日
老师好。我也有点问题。先补充一下你的答案，这个题我感觉不是必须告诉你yield curve stable，因为既然能用ride the yield curve，那么找到的yield curve必须是服从upward slpoing和stable的，不然S都不能ride the yield curve。我的问题是在最后一步。问的total return，这个年化。。。我有点糊涂
NO.PZ2018123101000027 问题如下 Smith gathers information on spot rates for on-the-run annual-coupon government securities answsprea, presentein Exhibit below.Smith buys a four-year, zero-coupon corporate bonanthen sell it after two years. Smith illustrates the returns from this strategy using the swrate a proxy for corporate yiel. Smith shoulshow a totreturn closest to: A.4.31%. B.5.42%. C.6.53%. C is correct.考点考察Ring the yielcurve策略解析由题干已知，Swrate来代替公司债的收益率；四年期的Swsprea差为0.70%，4年期的国债收益率Government spot rate 为4.05%，则4年期的swrate = 4.05% + 0.70% = 4.75%。因此，购买的4年期零息债券的价格为price=100(1+0.0475)4=83.058price=\frac{100}{{(1+0.0475)}^4}=83.058price=(1+0.0475)4100=83.058两年期的公司债收益率为2年期的Swrate, swrate = 2.70% +0.30% = 3%,4年期的零息债券持有2年后的卖出价格为price=100(1+0.0300)2=94.260price=\frac{100}{{(1+0.0300)}^2}=94.260price=(1+0.0300)2100=94.260则这笔投资的年化总收益为94.26083.058−1=0.0653=6.53%\sqrt{\frac{94.260}{83.058}}-1=0.0653=6.53\%83.05894.260−1=0.0653=6.53% 题目里面算出swrate，可以用它来折现？但是课上说swrate是一种prate？prate我理解就是每期现金流/pincipal的一个比率，应该是用来计算分子的？所以swrate到底是什么？为什么可以用来折现算价格？
NO.PZ2018123101000027 问题如下 Smith gathers information on spot rates for on-the-run annual-coupon government securities answsprea, presentein Exhibit below.Smith buys a four-year, zero-coupon corporate bonanthen sell it after two years. Smith illustrates the returns from this strategy using the swrate a proxy for corporate yiel. Smith shoulshow a totreturn closest to: A.4.31%. B.5.42%. C.6.53%. C is correct.考点考察Ring the yielcurve策略解析由题干已知，Swrate来代替公司债的收益率；四年期的Swsprea差为0.70%，4年期的国债收益率Government spot rate 为4.05%，则4年期的swrate = 4.05% + 0.70% = 4.75%。因此，购买的4年期零息债券的价格为price=100(1+0.0475)4=83.058price=\frac{100}{{(1+0.0475)}^4}=83.058price=(1+0.0475)4100=83.058两年期的公司债收益率为2年期的Swrate, swrate = 2.70% +0.30% = 3%,4年期的零息债券持有2年后的卖出价格为price=100(1+0.0300)2=94.260price=\frac{100}{{(1+0.0300)}^2}=94.260price=(1+0.0300)2100=94.260则这笔投资的年化总收益为94.26083.058−1=0.0653=6.53%\sqrt{\frac{94.260}{83.058}}-1=0.0653=6.53\%83.05894.260−1=0.0653=6.53% 关于持有两年后的价格计算，为什么不是用f（2,4）来折现，而是用S2来折现呢
NO.PZ2018123101000027 问题如下 Smith gathers information on spot rates for on-the-run annual-coupon government securities answsprea, presentein Exhibit below.Smith buys a four-year, zero-coupon corporate bonanthen sell it after two years. Smith illustrates the returns from this strategy using the swrate a proxy for corporate yiel. Smith shoulshow a totreturn closest to: A.4.31%. B.5.42%. C.6.53%. C is correct.考点考察Ring the yielcurve策略解析由题干已知，Swrate来代替公司债的收益率；四年期的Swsprea差为0.70%，4年期的国债收益率Government spot rate 为4.05%，则4年期的swrate = 4.05% + 0.70% = 4.75%。因此，购买的4年期零息债券的价格为price=100(1+0.0475)4=83.058price=\frac{100}{{(1+0.0475)}^4}=83.058price=(1+0.0475)4100=83.058两年期的公司债收益率为2年期的Swrate, swrate = 2.70% +0.30% = 3%,4年期的零息债券持有2年后的卖出价格为price=100(1+0.0300)2=94.260price=\frac{100}{{(1+0.0300)}^2}=94.260price=(1+0.0300)2100=94.260则这笔投资的年化总收益为94.26083.058−1=0.0653=6.53%\sqrt{\frac{94.260}{83.058}}-1=0.0653=6.53\%83.05894.260−1=0.0653=6.53% 相关公式可以写一下吗？
NO.PZ2018123101000027 问题如下 Smith gathers information on spot rates for on-the-run annual-coupon government securities answsprea, presentein Exhibit below.Smith buys a four-year, zero-coupon corporate bonanthen sell it after two years. Smith illustrates the returns from this strategy using the swrate a proxy for corporate yiel. Smith shoulshow a totreturn closest to: A.4.31%. B.5.42%. C.6.53%. C is correct.考点考察Ring the yielcurve策略解析由题干已知，Swrate来代替公司债的收益率；四年期的Swsprea差为0.70%，4年期的国债收益率Government spot rate 为4.05%，则4年期的swrate = 4.05% + 0.70% = 4.75%。因此，购买的4年期零息债券的价格为price=100(1+0.0475)4=83.058price=\frac{100}{{(1+0.0475)}^4}=83.058price=(1+0.0475)4100=83.058两年期的公司债收益率为2年期的Swrate, swrate = 2.70% +0.30% = 3%,4年期的零息债券持有2年后的卖出价格为price=100(1+0.0300)2=94.260price=\frac{100}{{(1+0.0300)}^2}=94.260price=(1+0.0300)2100=94.260则这笔投资的年化总收益为94.26083.058−1=0.0653=6.53%\sqrt{\frac{94.260}{83.058}}-1=0.0653=6.53\%83.05894.260−1=0.0653=6.53% 为什么2年后的卖出价格，不是用加上sprea的f(2,2)来折现100求得？
NO.PZ2018123101000027 问题如下 Smith gathers information on spot rates for on-the-run annual-coupon government securities answsprea, presentein Exhibit below.Smith buys a four-year, zero-coupon corporate bonanthen sell it after two years. Smith illustrates the returns from this strategy using the swrate a proxy for corporate yiel. Smith shoulshow a totreturn closest to: A.4.31%. B.5.42%. C.6.53%. C is correct.考点考察Ring the yielcurve策略解析由题干已知，Swrate来代替公司债的收益率；四年期的Swsprea差为0.70%，4年期的国债收益率Government spot rate 为4.05%，则4年期的swrate = 4.05% + 0.70% = 4.75%。因此，购买的4年期零息债券的价格为price=100(1+0.0475)4=83.058price=\frac{100}{{(1+0.0475)}^4}=83.058price=(1+0.0475)4100=83.058两年期的公司债收益率为2年期的Swrate, swrate = 2.70% +0.30% = 3%,4年期的零息债券持有2年后的卖出价格为price=100(1+0.0300)2=94.260price=\frac{100}{{(1+0.0300)}^2}=94.260price=(1+0.0300)2100=94.260则这笔投资的年化总收益为94.26083.058−1=0.0653=6.53%\sqrt{\frac{94.260}{83.058}}-1=0.0653=6.53\%83.05894.260−1=0.0653=6.53% 本题两个问题1.题目中没有说明spot rate曲线不变，是否应该增加此条件后题目才算严谨？2.求totreturn也要进行年化吗？什么情况下不需要年化呀？