问题如下：
A $100 million portfolio is allocated 70% to diversified stock portfolio and 30% to stock XYZ. The manager wants to decrease the exposure to XYZ and invest the fund to S&P 500 index by equity swap. The manager decides to reduce one-half of the XYZ position. Suppose six months later, the return on XYZ is 2% and the return on index is -1%. Calculate the net cash flow the manager needs to pay in six months.
选项：
A.$150,000
B.$450,000
C.$300,000
解释：
B is correct.
考点：equity swap
解析：
Manger应该进入一个支付XYZ收益，收到S&P500 index收益的equity swap。
注意投资经理只想减少一半的XYZ股票头寸，即100*0.3*1/2=15million，所以互换的名义本金为15million。
Net cash flow=（-XYZ return + index return）* NP=（-2%-1%）*15,000,000=-$450,000
因此，投资经理需要支付450,000的现金。
这个题目因为支付的return为正，而收到的return为负，所以就出现了支付两个return的现象。
这个return不用1/2是吗，不是年化的概念对吗，我后来用持有期收益算的否则就是2250
