Leverage can magnify investment gains—but it can magnify losses even faster.
When an investor borrows money to buy securities, falling prices can trigger a margin call.
If the investor cannot provide more cash, the broker may sell positions.
When this happens across many leveraged investors at once, forced selling can make a market decline much worse.
The basic chain is:
Falling Prices → Margin Calls → Forced Selling → More Falling Prices
Educational research only. This article is not investment advice.
What Is a Margin Call?
Buying on margin means borrowing money from a brokerage firm to purchase investments.
The securities in the account act as collateral for that loan.
Suppose an investor has:
- $50,000 of their own money;
- $50,000 borrowed from a broker.
They can now buy $100,000 of stock.
This doubles their market exposure.
But it also increases risk.
If the stock falls 20%, the investment is worth $80,000.
The broker is still owed $50,000.
So the investor’s equity has fallen from:
$50,000 → $30,000
A 20% market loss has therefore caused a 40% loss on the investor’s original capital.
That is leverage.
What Triggers a Margin Call?
Brokerages require investors to maintain a minimum amount of equity in a margin account.
FINRA generally requires equity of at least 25% of the current market value of long securities, although brokers can impose significantly higher requirements such as 30% or 40%.
A margin call can occur when:
- investments fall in value;
- an investor exceeds available buying power;
- the broker increases its margin requirement.
That last point is important.
A broker can raise its requirements during periods of extreme volatility.
So an investor can face additional pressure precisely when markets are already unstable.
Why Forced Selling Is Dangerous
A margin call usually requires the investor to restore enough equity.
They may do this by:
Adding cash
Depositing eligible securities
or:
Selling investments
If the investor cannot act quickly enough, the broker may liquidate positions.
FINRA warns that brokers generally do not have to let investors choose which securities are sold and may liquidate positions without first issuing a traditional warning call.
That creates a major difference between leveraged and unleveraged investors.
An ordinary investor may decide:
“I will hold through the decline.”
A highly leveraged investor may not have that option.
How Margin Calls Can Accelerate a Selloff
Imagine a popular stock falls sharply.
Leveraged investors begin losing account equity.
Some breach their margin requirements.
Their brokers sell shares.
Those sales push the stock lower.
That triggers margin calls for additional investors.
The feedback loop becomes:
Price Decline
↓
Account Equity Falls
↓
Margin Calls
↓
Forced Liquidation
↓
More Selling
↓
Further Price Decline
This process is sometimes called deleveraging.
It can turn a normal correction into a much more violent move.
A Recent Example
This risk remains very real.
In July 2026, AI-focused hedge fund Situational Awareness reportedly suffered a 67% portfolio decline after leveraged AI-stock positions moved sharply against it.
The losses triggered a margin call and forced the fund to liquidate most of its public-equity portfolio.
The lesson is not about one hedge fund.
It is that even sophisticated investors can lose control of their timing when leverage becomes too large.
Why Volatility Makes Margin Risk Worse
Margin becomes particularly dangerous when prices move quickly.
During high volatility:
- account values change rapidly;
- brokers may increase margin requirements;
- liquidity can disappear;
- forced selling can occur at poor prices.
Investors may therefore be forced to sell after a large decline rather than before one.
That is one reason leverage can produce losses far larger than expected.
How Risk Simulation Fits
TradingSimuLab’s Risk Simulation helps examine downside before focusing on potential return.
Relevant outputs include:
Max Drawdown
How far could the asset fall from a previous peak?
VaR
Where could severe downside begin?
CVaR
How damaging could losses become beyond that threshold?
Probability of Gain
How often do simulated paths finish above the starting level?
Terminal Price Range
How wide is the distribution of possible ending values?
These measures do not predict a margin call.
But they can help investors understand whether the underlying asset already carries substantial downside and path risk.
Leverage can then amplify that risk further.
Margin vs Unleveraged Investing
Consider the same 30% stock decline.
An unleveraged investor with $100,000 loses:
$30,000
A leveraged investor controlling $200,000 with only $100,000 of equity loses:
$60,000
Their asset fell 30%.
But their own capital fell 60%.
That is why position size and leverage can matter as much as being correct about market direction.
Final Takeaway
A margin call is not simply a warning that an investment has fallen.
It can force an investor to sell at exactly the wrong time.
The critical chain is:
Leverage → Falling Prices → Margin Call → Forced Selling → Larger Losses
And when many investors are leveraged simultaneously:
Forced Selling → More Forced Selling
That can contribute to market crashes.
The most important question is therefore not:
“How much can leverage increase my return?”
It is:
“How much can the market fall before leverage removes my ability to stay invested?”
For more market risk research, downside analysis and risk simulations, sign up to TradingSimuLab and explore the platform.