How Margin Calls Work: A Practical Guide for Traders

A margin call is one of the most important events a leveraged trader can understand before opening a position. It occurs when the value of the assets or account supporting a leveraged position falls below a required level, potentially requiring the trader to provide additional funds or reduce exposure.

For traders using margin loans, CFDs, futures or other leveraged products, a margin call can develop quickly when markets move against a position. If the required action is not taken, positions may be reduced or closed, potentially crystallising losses.

Understanding how margin calls work is therefore not simply an administrative exercise. It is a fundamental part of understanding leverage and managing trading risk.

This guide explains what triggers a margin call, how the process works, how margin calls differ across financial products, and what traders should consider before using leveraged exposure.

What Is a Margin Call?

A margin call is a demand for additional funds or action when an account no longer satisfies the required margin or loan-to-value conditions. The exact definition depends on the financial product. With a traditional margin loan, a margin call can occur when the loan-to-value ratio (LVR) rises above the level agreed with the lender. Moneysmart defines a margin call as occurring when the value of an asset falls below the agreed loan-to-value ratio, requiring the borrower to restore the agreed lending ratio.

With leveraged derivatives such as CFDs or futures, margin requirements work differently. A trader may be required to maintain sufficient funds in an account to support open positions. If losses reduce available equity below the relevant requirement, additional funds may be required or positions may be closed.

The underlying principle is similar: The market has moved against the leveraged position, reducing the financial buffer supporting it.

Why Do Margin Calls Happen?

Margin calls generally result from a deterioration in the relationship between the value of a leveraged position and the capital supporting it. There are several ways this can happen.

The underlying asset falls in value

For a margin loan, falling investments reduce the value of the portfolio while the amount borrowed may remain unchanged. Suppose a hypothetical investor has:

• $20,000 of their own capital
• $15,000 borrowed through a margin loan
• $35,000 invested in shares

The initial LVR is approximately 42.9%. If the shares fall in value to $25,000 while the loan remains $15,000, the LVR becomes 60%. The investment has fallen by approximately 28.6%, but the investor’s equity has fallen from $20,000 to $10,000-a 50% reduction. This is the effect of leverage: the debt does not automatically fall simply because the value of the investment has declined.

Losses reduce available margin

With leveraged derivatives, adverse price movements can reduce account equity and available margin. Moneysmart explains that CFD providers can require additional money when losses mean there is insufficient cash in the CFD account to cover the position. Depending on the circumstances, positions may then be closed. 

The position is too large relative to available capital

A trader using substantial leverage has a smaller financial buffer relative to the total market exposure. This means a relatively modest movement in the underlying market can produce a substantial change in the trader’s available equity. The problem is not necessarily the direction of the trade alone. It is the combination of position size, leverage and available capital.

How Does a Margin Call Work?

The process varies between products and providers, but the basic sequence can be illustrated in several stages.

Step 1: A leveraged position is opened

The trader provides an initial amount of capital or margin to establish exposure.

Step 2: The market moves against the position

The value of the underlying asset moves in an unfavourable direction.

Step 3: Account equity declines

The loss reduces the equity available to support the position.

Step 4: A required margin threshold is reached

The account no longer satisfies the applicable margin or LVR requirement.

Step 5: The trader must take action

Depending on the product, this could involve:

• Depositing additional funds
• Reducing the outstanding loan
• Adding eligible assets
• Closing part of the position
• Closing the entire position

Step 6: Positions may be liquidated

If the required action is not taken or if the product’s rules require automatic action the broker, lender or CFD provider may close positions. The important point is that a margin call does not necessarily mean the trader has control over the timing of the eventual exit. Market conditions can change rapidly, and automatic liquidation may occur at an unfavourable price.

Margin Calls on Margin Loans

Margin loans are a form of borrowing used to invest in assets such as shares, ETFs and managed funds.

In Australia, Moneysmart currently states that margin lenders generally require the LVR to remain below an agreed level. If the LVR rises above that level, a margin call can occur. The borrower can generally respond by depositing money, adding investments or selling part of the portfolio and reducing the loan. If the LVR cannot be restored, the lender may sell investments. Consider another hypothetical example.

A trader has a $25,000 investment portfolio and a $15,000 margin loan. The LVR is 60%. If the lender’s maximum LVR is 70%, the portfolio could decline to approximately $21,429 before the $15,000 loan represented 70% of the portfolio value, assuming the loan balance remains unchanged. At that point, the investor may receive a margin call. This simplified calculation does not account for interest, fees, changes in eligible security values or the lender’s specific terms.

Margin Calls on CFDs

CFDs operate differently from traditional margin loans. A CFD is a leveraged derivative that provides exposure to movements in an underlying asset without requiring the trader to own that underlying asset. For a CFD, the trader deposits margin to establish the position. As the market moves, the account’s equity changes. If losses reduce the account below the relevant margin requirements, additional funds may be required or positions may be closed.

Australian retail CFD clients are subject to ASIC’s product intervention framework, which includes restrictions on leverage, standardised margin close-out arrangements and negative balance protection. These protections are designed to reduce the speed and extent of retail client losses, but they do not make CFD trading low-risk.  ASIC’s Moneysmart guidance also warns that CFD trading is high risk and that leverage can magnify the effect of relatively small market movements.  The specific terms applying to an account should always be checked in the relevant product disclosure statement and client agreement.

Margin Call vs Margin Close-Out

These terms are related but should not be confused. A margin call generally refers to the requirement to provide additional funds or otherwise restore an account’s margin position. A margin close-out refers to the reduction or closure of positions when specified margin conditions are reached. The distinction matters because a trader may not always receive a conventional warning before a position is closed.

ASIC’s CFD framework standardises margin close-out arrangements for eligible retail CFD clients. These arrangements act as a circuit breaker intended to close positions before a retail client loses all or most of the funds invested in the CFD account.  However, traders should not interpret a close-out mechanism as a guarantee of a particular exit price or maximum loss in every conceivable market circumstance.

What Happens After a Margin Call?

The consequences depend on the financial product and its terms. For a margin loan, a borrower may need to restore the required LVR by providing additional cash, adding eligible investments or selling investments to reduce the loan. Moneysmart notes that borrowers may generally have a limited period to address a margin call, after which the lender can sell investments if the required LVR is not restored.  For leveraged derivatives, the provider may require additional funds or close positions when account requirements are breached. This creates an important risk-management lesson: A trader should understand the liquidation process before entering the position, rather than learning about it during a market decline.

Why Margin Calls Can Be Dangerous

The most significant risk is that a margin call can occur precisely when the trader’s portfolio is already under financial pressure.

Imagine a hypothetical investor whose portfolio has fallen sharply.

They may have three choices:

• Deposit additional cash.
• Sell investments to reduce exposure.
• Allow the lender or provider to close positions.

Each option has consequences. Adding money increases the amount of capital exposed to the market. Selling assets during a decline crystallises losses. Forced liquidation removes control over the timing of the sale. A further problem can arise when markets move extremely quickly. A position may decline faster than a trader can respond, or the market may gap between available prices. For this reason, a margin call should never be treated simply as a temporary inconvenience.

Common Mistakes Traders Make

Using the maximum available leverage

Access to leverage does not mean that maximum leverage is appropriate. The larger the position relative to available capital, the smaller the market movement required to produce a significant change in account equity.

Ignoring the loan balance

With margin lending, the investment may fall while the debt remains outstanding. This can cause the LVR to rise rapidly.

Assuming a margin call is predictable

Margin requirements can change according to market conditions, security values, account balances and provider terms. Traders should not rely on a single estimated price level.

Failing to keep accessible capital

A trader who has no readily available liquidity may be forced to sell assets or close positions at an unfavourable time.

Treating additional deposits as risk management

Adding money can restore a margin requirement, but it does not make the original trade less risky. If the underlying analysis is wrong, increasing the amount committed can increase potential losses.

Focusing on the margin instead of the exposure

A trader might see a $1,000 margin requirement and assume only $1,000 is at risk. That conclusion can be misleading. The economic exposure can be substantially larger, depending on the product.

How Traders Can Prepare for Margin Calls

The best time to manage margin risk is before opening the position.

Understand the product

Determine whether you are dealing with:

• A margin loan
• A CFD
• A futures contract
• Another leveraged derivative

The rules and obligations can differ substantially.

Calculate potential losses

Consider what would happen if the underlying market moved against you by several different amounts.

For example:

These are simplified hypothetical calculations before costs. The exercise demonstrates why position size matters.

Know the relevant thresholds

Before trading, identify:

• Initial margin requirement
• Maintenance requirements, where applicable
• Margin-call threshold
• Margin close-out level
• Time allowed to respond
• Circumstances allowing automatic liquidation
• Costs associated with financing and holding the position

Maintain a financial buffer

A position that leaves no spare capital can become difficult to manage during normal market volatility. Maintaining an appropriate buffer can reduce the chance that a temporary adverse movement immediately creates a forced decision.

Monitor positions appropriately

Leveraged positions require greater attention to risk than unleveraged holdings. That does not necessarily mean constantly watching every price movement. It means knowing when important market events, volatility changes or account-level thresholds could affect the position.

Can a Margin Call Be Avoided?

There is no method that can guarantee a margin call will never occur. However, traders can reduce the likelihood by controlling the factors within their influence. These may include:

• Using smaller positions
• Avoiding unnecessary leverage
• Maintaining adequate available capital
• Diversifying where appropriate
• Understanding margin requirements
• Monitoring account equity
• Establishing clear exit criteria
• Avoiding concentration in highly volatile assets

Risk management cannot eliminate market risk. Its purpose is to keep an adverse market scenario from becoming unnecessarily damaging.

Margin Calls and Australian Traders

Australian traders should distinguish between different forms of leveraged exposure rather than treating all margin arrangements as equivalent. For margin loans, Moneysmart describes borrowing to invest as a high-risk strategy because losses can be magnified while the loan and interest obligations remain.  For retail CFDs, ASIC’s product intervention framework provides specific protections, including leverage restrictions, margin close-out arrangements and negative balance protection. ASIC currently continues to monitor compliance with these requirements. 

These protections apply within their relevant regulatory scope and do not remove the need to understand the product’s terms. Rules, product structures and provider conditions can change. Traders should therefore review current documentation and regulatory information before relying on specific thresholds or procedures.

A Practical Margin Call Checklist

Before opening a leveraged trade, ask:

• What exactly triggers a margin call?
• What is the total market exposure?
• How much capital supports that exposure?
• What happens if the market moves 2%, 5% or 10% against me?
• What is the relevant margin or LVR threshold?
• Can the provider close my position automatically?
• How much time would I have to respond?
• What costs apply while the position remains open?
• Do I have sufficient accessible capital to manage an adverse move?
• Could I comfortably accept the potential loss without making an emotional decision?

If these questions cannot be answered clearly, the mechanics of the trade may not yet be sufficiently understood.

Key Takeaways

A margin call is fundamentally a warning that the financial buffer supporting a leveraged position has become too small. The most important points are:

• A margin call can occur when an account no longer satisfies the required margin or LVR conditions.
• Falling asset values can cause an LVR to rise on a margin loan.
• Losses on leveraged derivatives can reduce account equity and available margin.
• A trader may need to deposit funds, reduce exposure or sell assets.
• Positions may ultimately be closed if requirements are not met.
• Margin calls can occur during periods of rapid market volatility.
• Using more leverage creates greater sensitivity to relatively small market movements.
• Margin close-out arrangements are not the same as a guarantee against losses.
• Australian retail CFD clients have specific regulatory protections, but leveraged trading remains high risk.
• Understanding the product’s margin rules before entering a trade is an essential part of responsible risk management.