问题如下：
Initially, Fund TMT held active positions in two realestate stocks—one was overweight by 1 %, and the other was underweight 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 risk? TMT’s active risk:
选项：
A.decreased.
B.remained unchanged.
C.increased.
解释：
C is correct.
考点：Active Share and Active Risk
解析：主动风险受股票之间相关性的影响。不同行业的两只股票的相关性低于同一行业两只股票的相关性。因此，新头寸（汽车/科技股）的相关性低于初始头寸(房地产/房地产)的相关性。两只股票的相关性较低，两只股票头寸对主动风险的贡献就越大。
这里不是问组合和benchmark的风险吗？ benchamrk是TMT行业的啊，这个组合名字都叫TMT组合，调仓前组合里是地产股，和benchmark的相关性最低，那就应该AR更高，调仓以后有一只科技股，那这样就和benchmark的相关性高了，相关性高不是应该AR低吗？所以调仓前后对比的话，AR应该更低了啊
