NO.PZ2018120301000037
问题如下:
Schuylkilland Chaopraya now discuss Option 2. Chaopraya estimates the present value ofthe four future cash flows as $230,372, with a money duration of $2,609,700 andconvexity of 135.142. She considers three possible portfolios to immunize thefuture payments, as presented in Exhibit 2.
Determinethe most appropriate immunization portfolio in Exhibit 2. Justify yourdecision.
解释:
Answer:
Justification:
Portfolio2 is the most appropriate immunization portfolio because it is the only onethat satisfies the following two criteria for immunizing a portfolio ofmultiple future outflows:
- Money Duration: Money durations of all three possible immunizing portfolios match or closely match the money duration of the outflow portfolio. Matching money durations is useful because the market values and cash flow yields of the immunizing portfolio and the outflow portfolio are not necessarily equal.
- Convexity:Given that the money duration requirement is met by all three possibleimmunizing portfolios, the portfolio with the lowest convexity that is abovethe outflow portfolio’s convexity of 135.142 should be selected. Thedispersion, as measured by convexity, of the immunizing portfolio should be aslow as possible subject to being greater than or equal to the dispersion of theoutflow portfolio. This will minimize the effect of non-parallel shifts in theyield curve. Portfolio 3’s convexity of 132.865 is less than the outflowportfolio’s convexity, so Portfolio 3 is not appropriate. Both Portfolio 1 andPortfolio 2 have convexities that exceed the convexity of the outflow portfolio,but Portfolio 2’s convexity of 139.851 is lower than Portfolio 1’s convexity of147.640. Therefore, Portfolio 2 is the most appropriate immunizing portfolio.
Theimmunizing portfolio needs to be greater than the convexity (and dispersion) ofthe outflow portfolio. But, the convexity of the immunizing portfolio should beminimized in order to minimize dispersion and reduce structural risk
有没有一个门槛比例之类可以界定,我感觉200多又不算相差的少,但是答案有这么写,想怎么解释都是按照答案来倒推,下次遇见类似的还是拿不准