问题如下：
Sigma Investment manages a portfolio for an institutional client. The client instructs the firm to change its portfolio’s mandate from a short duration bond portfolio to an intermediate duration bond portfolio. Therefore, Sigma Investment decides to put the original short duration bond portfolio into another composite. In order to comply to the GIPS standards, the historical performance of the portfolio must:
选项：
A. be removed from the original composite
B. be recorded in both the original and new composites.
C. remain with the original composite.
解释：
C is correct.
考点：3.A Composite construction-3.A.7
解析：条款3.A.7 Portfolios must not be switched from one composite to another unless documented changes to a portfolio’s investment mandate, objective, or strategy or the redefinition of the composite makes it appropriate. The historical performance of the portfolio must remain with the original composite.
一般情况下一个组合不得从一个Composites中被移出或是被编入另一个Composites中。除非有记录文件表明该投资基金的投资风格、投资目标、投资策略发生了重大改变，或者是composite本身定义出现了改变。组合的历史业绩必须保留在原composite中。
b为什么错。。。。。