谁给我讲讲short的时候Margin的算法吧。 - 未名空间MITBBS历史存档

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谁给我讲讲short的时候Margin的算法吧。

谁给我讲讲short的时候Margin的算法吧。# Stock

n*n2011-09-03 07:09

1 楼

比如我有1k cash, 我能short面值多于1k的股票吗？
按道理讲，应该是可以的，但是IB好像会margin call如果我short以后的margin大于
liquidity value of my account.
这是什么算法？

v*m2011-09-03 07:09

2 楼

The reason that margin accounts and only margin accounts can be used to
short sell stocks has to do with Regulation T, a rule instituted by the
Federal Reserve Board. This rule is motivated by the nature of the short
sale transaction itself and the potential risks that come with short selling
.
Under Regulation T, it is mandatory for short trades that 150% of the value
of the position at the time the short is created be held in a margin account
. This 150% is comprised of the full value of the short (100%), plus an
additional margin requirement of 50% or half the value of the position. (The
margin requirement for a long position is also 50%.) For example, if you
were to short a stock and the position had a value of $20,000, you would be
required to have the $20,000 that came from the short sale plus an
additional $10,000, for a total of $30,000, in the account to meet the
requirements of Regulation T.
The reason you need to open a margin account to short sell stocks is that
shorting is basically selling something you do not own. As the short
investor, you are borrowing shares from another investor or a brokerage firm
and selling it in the market. This involves risk, as you are required to
return the shares at some point in the future, which creates a liability or
a debt for you. It is important for you to bear in mind that it's possible
for you to end up owing more money than you initially received in the short
sale if the shorted security moves up by a large amount. In such a situation
, you may not be financially able to return the shares. Therefore, margin
requirements are essentially a form of collateral, which backs the position
and reasonably ensures that the shares will be returned in the future.
A margin account also allows your brokerage firm to liquidate your position
if the likelihood that you will return what you've borrowed diminishes. This
is part of the agreement that is signed when the margin account is created.
From the broker's perspective, this increases the likelihood that you will
return the shares before losses become too large and you become unable to
return the shares.
Read more: http://www.investopedia.com/ask/answers/05/marginaccountshortsell.asp#ixzz1Ww8NZN4T

【在 n******n 的大作中提到】

: 比如我有1k cash, 我能short面值多于1k的股票吗？
: 按道理讲，应该是可以的，但是IB好像会margin call如果我short以后的margin大于
: liquidity value of my account.
: 这是什么算法？

n*n2011-09-03 07:09

3 楼

Thanks.

selling
value
account
The

【在 v**********m 的大作中提到】

: The reason that margin accounts and only margin accounts can be used to
: short sell stocks has to do with Regulation T, a rule instituted by the
: Federal Reserve Board. This rule is motivated by the nature of the short
: sale transaction itself and the potential risks that come with short selling
: .
: Under Regulation T, it is mandatory for short trades that 150% of the value
: of the position at the time the short is created be held in a margin account
: . This 150% is comprised of the full value of the short (100%), plus an
: additional margin requirement of 50% or half the value of the position. (The
: margin requirement for a long position is also 50%.) For example, if you