How to Avoid a Margin Call
To avoid a margin call, keep account equity well above the maintenance requirement rather than close to it, and size positions so ordinary adverse movement cannot reach the threshold. Requirements can also be raised without notice, which is why the buffer needs to be substantial.
A margin call is the broker requiring more equity or closing positions to restore it. It is entirely avoidable, and the thing that avoids it is a buffer — not a tighter stop, because the stop protects a position while the buffer protects the account.
Before you start
The maintenance requirement for your account and the instruments in it. It differs by instrument and by broker, and it is in the account documents.
An understanding that requirements can be raised without warning. Brokers increase them on volatile names and in volatile conditions, and your existing position is subject to the new figure.
A buffer large enough that ordinary movement never approaches the threshold. On this site’s shared series the largest single bar measured 2.338 against a median of 0.493.
The steps
1. Find your maintenance requirement
The equity percentage below which the call triggers. Written down, per instrument type, before any position is opened.
2. Calculate how far price can move before you reach it
One arithmetic step that almost nobody performs. If the answer is a distance the instrument covers in a normal week, the position is too large.
3. Keep your own stop far inside it
The stop should trigger long before the broker’s threshold is approached. If it cannot, the position is sized for the account rather than for the trade.
4. Add correlated positions together
Margin calls rarely come from one position. They come from several that all moved the wrong way at once, which is what correlated positions do.
5. Hold a cash buffer that is not doing anything
Uninvested equity is what absorbs an adverse move and a raised requirement. It feels inefficient and it is the only thing standing between a bad week and a forced liquidation.
6. Reduce before the call, not after
If equity is approaching the threshold, close something yourself. You choose which position and when; the broker’s process chooses neither.
7. Check the requirement periodically
It changes, particularly during volatile periods and on individual names. A weekly check takes a minute and catches the version of this problem that has nothing to do with your trading.
How to tell it worked
The maintenance requirement is written down for every instrument you hold.
Your stop sits at least 3 times closer than the margin threshold.
Combined exposure across correlated positions was computed, not just per trade.
And 0 margin calls have occurred, because equity never approached the line.
What forced liquidation actually does
The broker chooses what to close and when. Not the position you would have picked, not at a price you would have chosen, and typically during a fast market when spreads are widest.
And it happens at the worst point of the move. By construction, the call arrives when things are at their worst, which is the moment a forced sale is most expensive.
Why a buffer beats a tighter stop
A stop protects one position. It fires at a level you chose, on that instrument, and it does nothing about the other four open at the same time.
A margin call is an account-level event. It happens when total equity falls, which can occur with every individual stop still comfortably intact.
Which is why the defence has to be at the account level too. Idle cash, and a combined exposure well below what the account permits. Both feel wasteful during good stretches, and both exist for the week where several things go wrong at once.
Initial against maintenance margin
Initial margin is what you need to open the position. It is the larger number and the one most people are aware of, because it is checked at the moment of entry.
Maintenance margin is what you need to keep it. It is lower, it is checked continuously, and it is the one that triggers the call.
The gap between them is where the false comfort lives. A position opened at exactly the initial requirement has only the difference between the two figures as its cushion, which on many instruments is a small fraction of a normal week’s movement.
Which is why the useful question is never “can I open this”. It is “how far can this move against me before the maintenance figure is breached” — and that number is the one worth computing before every position rather than after the first uncomfortable one.
What the account agreement actually permits
The broker can liquidate without contacting you. Most agreements say so explicitly, and the expectation of a warning call is a convention rather than a right.
They can raise requirements on existing positions. Held positions are subject to the new figure, not the one in force when they were opened.
And they choose the order of liquidation. Typically whatever restores the requirement fastest, which is frequently the position you would least have chosen to close.
The original data
Of the 24,971 unique videos in research/search-study-corpus.jsonl, 0 mention margin calls in the
title. Margin generally appears in 34 at a median of 28,191, leverage in 68 at 27,019 and risk
management in 410 at 4,079. The counts come from site/corpus_count.py.
0 videos on the event that ends leveraged accounts, against 68 on leverage itself at 27,019 views. The mechanism is taught enthusiastically and its characteristic failure has no coverage at all.
The answer to the question on that chart is that 5% is inside a single bad session. On this site’s series the largest bar measured 2.338 against a median of 0.493 — closing something yourself, now, is the version of this where you choose what goes.
When it fails
The failure is several correlated positions and no cash buffer, and it arrives as one event. Each position was sized sensibly against its own stop. All four are in related instruments, so a single market-wide move takes them all the same way at once. Total equity falls below the threshold while every individual stop is still untouched — and the broker liquidates whichever positions restore the requirement, at the worst prices of the week, on a schedule nobody chose.
The second failure is not knowing the requirement. You cannot compute the distance.
A third is a fully invested account. There is nothing to absorb a move.
A fourth is treating positions separately. Margin is account-level.
A fifth is waiting for the call. Closing early keeps the choice yours.
And a sixth is assuming the requirement is fixed. It can rise while you hold.
Related
Margin account covers how requirements are calculated. Leverage trading is what creates the exposure. And risk management is the framework the buffer belongs to.
The part that surprised me is that the requirement itself can change. A position sized comfortably against one maintenance level became uncomfortable when the broker raised it during a volatile week — and nothing about my position had changed. The buffer has to absorb that as well as the market.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.