In: Finance
Consider a self-financed convexity trade.
Three zero couple bonds:
i. 2Y zero at 1.60%; ii. 10Y zero at 1.85%; iii. 30Y zero at 2.30%
a. If you want to combine 2Y and 30Y zero to match the $100M bullet in 10Y zero for dollar duration, what is percentage weights in 2Y and 30Y respectively? (note: combined value in 2Y and 30Y is also $100M, ie weights sum up to 100%)
| Duration of a Zero Coupon Bond is equals to its maturity. | ||||||||
| Also duration of portfolio bond is equal to weighted average | ||||||||
| duration of all bonds in the portfolio. | ||||||||
| Duration of 2 year Zero Coupon Bond = 2 Years | ||||||||
| Duration of 10 year Zero Coupon Bond = 10 Years | ||||||||
| Duration of 30 year Zero Coupon Bond = 30 Years | ||||||||
| Let the weight of 2 Year Zero Coupon Bond be "x" | ||||||||
| then weight of 30 Year bond will become "1-x". | ||||||||
| This should be matched with duration of 10 year zero | ||||||||
| coupon bond. | ||||||||
| So, | ||||||||
| Duration of 10 Year Zero Coupon Bond | ||||||||
| = Duration of 2 Year Zero Coupon Bond * Weight of 2 Year Bond | ||||||||
| + Duration of 30 Year Zero Coupon Bond * Weight of 30 Year Bond | ||||||||
| 10 = 2 * x + 30 * (1-x) | ||||||||
| 10 = 2 * x + 30 - 30*x | ||||||||
| 10 = 30 - 28*x | ||||||||
| 28 * x = 30-10 | ||||||||
| 28 * x = 20 | ||||||||
| x = 0.7143 | ||||||||
| Weight of 2 Year Zero Coupon Bond = x = 0.7143 = 71.43% | ||||||||
| Weight of 30 Year Zero Coupon Bond = 1-x = 1-0.7143 = 0.2857 = 28.57% | ||||||||