NO.PZ2018062007000060
问题如下：
Which of the following statements describes an aspect of margin accounts for futures?
选项：
A.
The maintenance margin is always less than the initial margin.
B.
The initial margin required is typically at least 10% of the futures price.
C.
A margin call requires a deposit sufficient to raise the account balance to the maintenance margin.
解释：
A is correct. The maintenance margin is always significantly lower than the initial margin. B is incorrect because the initial margin required is typically at most (not at least) 10% of the futures price. C is incorrect because a margin call requires a deposit large enough to bring the balance up to the initial (not maintenance) margin.
中文解析：
A对，A说的是maintenance margin（维持保证金）通常小于initial margin（初始保证金）。
B错，因为初始保证金要求是小于等于期货价格的10%，而不是最少是期货价格的10%。
C错，接到margin call 的时候需要将保证金的账户补到初始保证金的水平。
有个点一直没整明白 收到margin call equity是按比例补到MM水准，所以一直跌就得一直补但绝对金额在下降 derivative是按金额补回到initial margin当初的金额，所以不存在按比例少补？比如¥100的contract，initional margin给了¥30，极端点就算contract跌到了¥20，要补还是得补到¥30那么多？
