问题如下：
Judy, a financial analyst, met three important clients and talked about their investment strategies separately this morning.
Client 1: I prefer to use long option during the investment, because in my experience long option position gives me excess returns with small risk. I am sure it has low probability of loss and will invest more long option products in the future.
Client 2: I have 25 years of investment experiences. I know that market prices can be affected by emotions of investors, therefore I focus on the buy and sell signals. I trust those analysts who also take price-volume analysis into consideration.
Client 3: I have my own investment strategy, which proves to outperform most investors' strategies: I sell a stock when its price goes up by 10% or when its price goes down by 15%.
Which client least likely support the weak form of efficient market hypothesis?
选项：
A.Client 1.
B.Client 2.
C.Client 3.
解释：
B is correct.
考点：efficient market hypothesis，传统金融学
解析：如果weak form of efficient market hypothesis成立，技术分析是无法获得超额收益的。本题题干指出，要找到哪位客户不支持弱式有效市场假说，也就是这个客户认为技术分析是可以获得超额收益的。 Client 2 关注buy and sell signals和price-volume analysis，这些都是技术分析常用的方法。技术分析所研究的anomaly确实是来源于投资者的非理性决策，非理性的决策比如说追涨杀跌，追涨会使价格持续上涨，杀跌会让价格持续下跌，因此技术分析师可以通过价格趋势找到市场异常。所以选B。
本题常见错误是选Client 3。Client 3对待价格上涨和下跌的态度是不对称的，上涨到10%但下跌到15%才卖出，所以是Loss aversion, loss aversion属于行为金融学范畴。
老师您好，我记得上涨慢下跌快能得出投资者的utility function是concave的，所以是风险厌恶的，但是这道题答案中解释上涨10%或者下跌15%才肯卖出就说明投资者是风险厌恶的，怎样去理解它呢？
