问题如下：
Mr. Han manages an $52million US equity portfolio. He expects that equity market is very promising in the near term and would like to have more exposure on the systematic risk. Current portfolio beta is 0.9, and he thinks 1.2 is the optimal. The S&P 500 futures index is currently trading at 950 with a multiplier of 250. In order to achieve his objective, which of the following strategy should be implemented?
选项：
A.Buy 52 contracts .
B.Sell 52 contracts .
C.Buy 66 contracts .
D.Sell 66 contracts .
解释：
C is correct.
考点：Hedging With Stock Index Futures
解析：题目需要利用股指期货调整股票的风险情况。首先判断方向，因为预期股票市场未来会更乐观，所以是要增加股票的风险，因此是要买入S&P 500股指期货。
接下来计算需要购买多少份，
number of contracts
= (target beta - current beta) x (portfolio value / futures value)
= (1.2 – 0.9) x [$52 million / (950 x 250)] = 65.68 ≈ 66 ( buy 66 contracts)
beta的意义不是组合（相当于大盘）的活跃程度吗？那为什么beta<1的组合（不如大盘活跃）和beta=1的大盘组合之后beta可以大于1？虽然会照本宣科的做题，但是逻辑上还是不理解。
