NO.PZ2019012201000031
问题如下：
Initially, Fund TMT held active positions in two realestate stocks—one was over-weighted by 1 %, and the other was under-weighted by 1%. Fund TMT traded back to benchmark weights on those two stocks. Then, TMT selected two different stocks that were held at benchmark weights, one automobile stock and one technology stock. TMT over-weighted the automobile stock by 1% and underweighted the technology stock by 1%. What was the effect of TMT’s two trades on its active share? TMT’s active share:
选项：
A.decreased.
B.remained unchanged.
C.increased.
解释：
B is correct.
考点：Active Share and Active Risk
解析：只有当投资组合的主动权重绝对值的总和发生变化时，主动份额才会发生变化。在TMT基金的两笔交易中，初始头寸和新头寸都涉及两只股票，一只减持1%，另一只增持1%，因此主动权重绝对值的总和没有变化，所以主动份额并没有改变。
我以为题目的意思是TMT中原本只有两只股票，且股票与假设本身有100只股票的benchmark相同。后来又增加了两只benchmark中有的股票。
但是weight的方面我又没办法理解。如果只有两只股票，怎么做到和比如本来有100只股票的benchmark权重只差1%？
然后我的逻辑是本来TMT只有两只，现在多了两只变4只，在向benchmark靠近了，所以activeshare在减少。
所以TMT和benchmark的股票结构以及weight我该怎么理解？
