Estimating a Stock Liquidation Price from Margin Requirements
Summary
The document examines how a brokerage’s initial and maintenance margin requirements relate to the stock price at which a leveraged position may be liquidated. The author presents a formula based on cash borrowed per share and the maintenance margin rate, then tests it with a hypothetical purchase of shares using the account’s full buying power.
That example appears to imply liquidation at the entry price, leading the author to question the formula or the stated margin assumptions. The post does not establish that the formula is correct or explain broker-specific liquidation rules. Actual outcomes may depend on account-level margin calculations and brokerage policies, which the text does not address.
Key ideas
- The author relates a position’s borrowing, share count, and maintenance margin rate to a proposed liquidation price.
- A hypothetical fully leveraged stock purchase is used to question whether the formula implies immediate liquidation.
- The post reports margin figures attributed to a broker but does not verify their applicability.
- It leaves the calculation unresolved and does not cover account-level or broker-specific liquidation procedures.
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Full text
# How to Determine the Last Stock Price Before We Begin to Liquidate the Position on Interactive Brokers?
# How to Determine the Last Stock Price Before We Begin to Liquidate the Position on Interactive Brokers?
I do not if it is me who is wrong or Interactive Brokers' employees who do not provide a clear information by phone about How to Determine the Last Stock Price Before They Begin to Liquidate the Position
They say that for a Margin account to trade stocks the
$\text{Initial Margin} = 25 \% $ (This matches with the Buying power of IB that is 4 times the Equity)
$\text{Minimum Maintenance Margin} = 25 \%$ (This part should be different because the MInimum Maintenance Margin is less than the Initial Magin. I will explain this with an example )
According to them, the formula is:
$\dfrac{(\text{Cash borrowed}) / (\text{number of shares})}{1 - \text{margin rate}} = \text{last price before liquidation}$
Example of the apparent contradiction
Suppose that you are a day trader who are interested in holding your position during the day, from 9:30 AM to maximum 11:30 AM. In this case, and if you buy 2000 shares of MU at $\$50$ per share, you will be using all of your Buying Power, and you will be receiving margin calls for any drop on MU price because
$$ \text{last price before liquidation} = \dfrac{(\$ 100000) (1 - 0.25) / (2000 )}{1 - 0.25} = \$50 $$
by the way
$\text{Cash Borrowed} = (\text{stock value})(1-\text{Initial Margin}) $ $\text{Stock Value} = 2000 \text{shares} * (50 \text{dollars per share}) = \$ 100000$ $\text{Margin Rate} = \text{Minimum Maintenance Margin}$
I would really appreciate any help with this problem. Thanks in advance.Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.