idiosyncratic risk.能才解释一下么

NO.PZ201809170400000505 问题如下 Relative to Fun1, Chiyosenko’s new equity funwill most likely exhibit a lower: information ratio. iosyncratic risk. collaterrequirement. A is correct. the new funscales up active risk ubling active weights, it will faimplementation constraints thwill prevent it from increasing the weights of many of its short positions. The information ratio (IR) is finethe ratio of active return to active risk. If there were no constraints preventing the new funfrom scaling up active weights, it coulscale up active risk scaling up active weights, proportionally increase active return, ankeep the IR unchange Implementation constraints experiencethe new fun however, suthe cost anfficulty in borrowing securities to support the scaleup short positions, will prevent the active return from proportionally increasing with the active risk. Therefore, the IR woulmost likely lower for the new funthfor Fun1. the following chart illustrates, active risk is scaleup, implementation constraints create minishing returns to scale for active returns, theregrang the IR. 可以一下推导过程吗？

NO.PZ201809170400000505问题如下 Relative to Fun1, Chiyosenko’s new equity funwill most likely exhibit a lower: information ratio. iosyncratic risk. collaterrequirement. A is correct. the new funscales up active risk ubling active weights, it will faimplementation constraints thwill prevent it from increasing the weights of many of its short positions. The information ratio (IR) is finethe ratio of active return to active risk. If there were no constraints preventing the new funfrom scaling up active weights, it coulscale up active risk scaling up active weights, proportionally increase active return, ankeep the IR unchange Implementation constraints experiencethe new fun however, suthe cost anfficulty in borrowing securities to support the scaleup short positions, will prevent the active return from proportionally increasing with the active risk. Therefore, the IR woulmost likely lower for the new funthfor Fun1. the following chart illustrates, active risk is scaleup, implementation constraints create minishing returns to scale for active returns, theregrang the IR. 如题

NO.PZ201809170400000505 iosyncratic risk. collaterrequirement. A is correct. the new funscales up active risk ubling active weights, it will faimplementation constraints thwill prevent it from increasing the weights of many of its short positions. The information ratio (IR) is finethe ratio of active return to active risk. If there were no constraints preventing the new funfrom scaling up active weights, it coulscale up active risk scaling up active weights, proportionally increase active return, ankeep the IR unchange Implementation constraints experiencethe new fun however, suthe cost anfficulty in borrowing securities to support the scaleup short positions, will prevent the active return from proportionally increasing with the active risk. Therefore, the IR woulmost likely lower for the new funthfor Fun1. the following chart illustrates, active risk is scaleup, implementation constraints create minishing returns to scale for active returns, theregrang the IR. 选择2是啥意思呢？谢谢

    如题，如果无成本限制等，在完美情形下，scale up Information ratio 不变。这里想和Sharp ratio cgame一个对比，Sharp ratio时间拉长，eg 从月到年，相当于分子return增长12倍，但分母stanrviation 未同比例增长，只增长了genghao根号12倍，导致Sharp ratio变大。这两个知识点感觉从数学原理上是一样的，为什么导出结果 一个是不变 一个是变大呢？求指点。