Margin account requirements: what investors should know
Published: Sep 25, 2026
Understanding margin account requirements starts with knowing how margin buying power works. Margin account buying power is the amount you might be able to use to buy or short eligible securities based on factors such as available cash, account equity, eligible holdings, borrowed funds, and margin requirements.
Unlike cash buying power, which uses only the money in your account, margin buying power might include funds or securities borrowed from your brokerage. This could increase purchasing and selling capacity but also increase potential gains and losses.
Margin buying power is not fixed and could change as market values move, trades are placed, or margin requirements are updated.
What does margin buying power mean?
Buying power is sometimes assumed to be the same as withdrawable cash, but the two work differently. Margin buying power is the potential amount available to purchase eligible securities, sell short, or, in some cases, withdraw as borrowed cash, based on factors such as available cash, account equity, eligible investments, existing margin borrowing, and margin requirements.
Buying power allows an investor to purchase more securities than their available cash would otherwise support, and similarly allows for larger short positions than cash alone would permit, since margin borrowing effectively extends purchasing and short-selling capacity beyond the account's cash balance.
Unlike a cash account, margin buying power might include both your own funds and money borrowed from your brokerage. Because of this, it does not represent cash available to withdraw or transfer.
The amount available to trade depends on several factors, including:
The type of security being purchased
Whether the security is eligible for margin
The account’s current positions
Margin requirements set by the brokerage or applicable rules
For example, two accounts with the same cash balance might have different buying power depending on the securities they hold and their margin requirements.
Buying power shows how much you could buy. Cash shows how much money is actually in your account.
How margin account buying power works
In a margin account, buying power depends on your account value and the margin requirements for the securities you want to buy. A margin account allows eligible investors to borrow funds from their brokerage using account assets as collateral.
Key factors include:
Account equity: The value of your account after subtracting borrowed funds.
Cash balance: The cash available in your account, which is one factor that affects buying power.
Borrowed funds: Money borrowed from the brokerage that could increase buying power but might include interest costs.
Eligible securities: Investments that qualify for margin. Requirements could vary by security.
Initial margin requirement: The equity needed to open a new position.
Maintenance margin requirement: The minimum equity needed to keep a position open.
Securities with lower margin requirements might provide more buying power than those with higher requirements. These factors are why margin buying power could differ between accounts and change over time.
How is margin buying power calculated?
Margin buying power is influenced by your account equity and the security’s margin requirement. A margin requirement determines how much of the purchase must come from your own funds and how much might be available through borrowing.
For example, if you have $10,000 in account equity and a security has a 50% margin requirement, you might have up to $20,000 in buying power for that security in a simplified example. This is because you provide half of the purchase amount and might borrow the rest.
Higher requirements usually mean lower buying power because more of the purchase must come from your own funds. Buying power could also change after trades or market movements.
This is a simplified example for educational purposes only. Actual margin buying power might vary based on account details, security eligibility, currency, open orders, concentration, and brokerage requirements.
Margin buying power vs. cash buying power
Cash buying power is the money you already have in your account and could use to buy securities without borrowing.
Margin buying power might include your cash plus funds you could borrow from your brokerage. It depends on your account value, margin requirements, and the securities you want to buy. Because it involves borrowing, it might include interest costs and additional risk.
Cash buying power is generally more stable, while margin buying power could change with market movements, account value, open orders, and margin requirements.
In simple terms, cash buying power is the money you have, while margin buying power is the money you might be able to use through borrowing.
What affects your margin account buying power?
Your margin account buying power is not fixed and might increase or decrease throughout the day.
Here are the main factors that affect it:
Market value of your holdings: If your investments rise in value, buying power might increase. If they fall, buying power might decrease as account equity changes.
Margin requirements for securities: Securities have different requirements. Higher requirements reduce buying power, while lower requirements might increase it.
Open orders: Funds set aside for pending trades are not available, which reduces buying power.
Existing margin loans: If you have already borrowed on margin, it reduces how much additional buying power you have.
Deposits or transfers not yet cleared: Deposits might not immediately increase buying power until they fully settle.
Currency timing (if applicable): Exchange rate changes or settlement timing could affect buying power in multi-currency accounts.
Brokerage or regulatory changes: Updates to margin rules could increase or decrease buying power.
Overall, margin buying power changes based on your account activity, market movements, and applicable margin requirements.
Why your margin buying power might be lower than expected
Sometimes your buying power might feel lower than your account balance. This could happen if:
A security is not eligible for margin
The margin requirement for a security is high
You have a concentration in one stock or sector
Open orders or existing margin use is reducing available capacity
Overall, margin buying power reflects real-time borrowing capacity, not a fixed amount of cash.
What are margin requirements
Margin requirements explain how much of a security’s purchase price must be covered by your own money (account equity) when using a margin account. They help determine how much you might be able to borrow and how much you need to contribute.
Different securities could have different margin requirements. Some might require more of your own funds, while others might allow more borrowing. Some securities might not be eligible for margin and must be purchased with cash.
Margin requirements affect buying power:
Higher requirements might reduce how much you could buy
Lower requirements might increase buying power, depending on your account equity
The two main types are:
Initial margin requirement: The equity needed to open a position
Maintenance margin requirement: The minimum equity needed to keep a position open
If your account equity falls below the maintenance margin requirement, your brokerage might ask you to add funds or reduce positions. Depending on your account terms, positions might also be adjusted or closed.
What happens if your buying power drops?
Your margin buying power could change as your investments and account conditions change. A decrease does not always mean something is wrong and might reflect market movements, open orders, or margin requirement changes.
If buying power decreases, you might not be able to place new margin trades because your borrowing capacity is reduced.
You might need to take action, such as:
Depositing funds
Adding eligible securities
Reducing or closing positions
If your account equity falls below maintenance margin requirements, a margin call occurs. Your brokerage will ask you to restore your account, and positions might be adjusted or sold if needed.
Other key points:
Market volatility could cause buying power to change quickly
Margin uses borrowed money, so losses might be magnified
Declines in value could reduce buying power and trigger required actions
Risks to understand before using margin buying power
Margin accounts could increase buying power, but they also come with important risks.
Margin is borrowed money: You are borrowing from your brokerage, not using extra cash.
Interest might apply: Borrowed funds could accrue interest over time, even if investments don’t change in value.
Losses might be larger: If investments decline, losses could exceed what you would face in a cash-only account because borrowed money must still be repaid.
Buying power could change quickly: Market movements and margin requirement changes could increase or decrease buying power without notice.
If your account value drops too far, you might receive a margin call.
Because of these risks, it is important to understand margin accounts clearly before use.
Common misconceptions about margin buying power
Many investors misunderstand what margin buying power represents, which could lead to confusion when looking at their accounts.
“My buying power is cash I could withdraw.”
This is not true. Buying power is not the same as withdrawable cash and does not mean the money could be taken out of the account.
“Higher buying power means I should use it.”
Not necessarily. Higher buying power simply reflects borrowing capacity, not a recommendation to trade or take on more risk.
“My buying power will stay the same.”
Buying power could change at any time based on market movements, account value, open orders, or margin requirement updates.
“All securities have the same margin requirement.”
Different securities could have different margin requirements. Some might require more of your own funds, while others might not be eligible for margin at all.
“If I have buying power, every trade will be approved.”
Not always. A trade might still be declined if the security is not eligible, if requirements change, or if there is not enough available margin for that specific purchase.
These misunderstandings are common because margin numbers could look similar to cash balances, but they represent borrowing capacity rather than available cash.
A quick checklist before using margin buying power
Before using margin buying power, it helps to ensure you understand how it works and what it means for your account. Here’s a quick checklist:
Do I understand that margin is borrowed money?
Do I know the margin requirement for the security I want to buy?
Could I handle a margin call if my account value drops?
Do I understand that interest might apply to borrowed funds?
Am I comfortable with the possibility of larger losses compared to a cash-only account?
Do I understand that buying power could change as market prices move?
Understanding margin buying power before you trade
Margin buying power is your potential purchasing capacity in a margin account. It is based on account equity, available cash, and margin requirements for the securities you want to buy. Because these factors could change, buying power is not fixed and might rise or fall with market movements.
It is not the same as cash. Cash is money you already have, while margin buying power might also include funds you could borrow from your brokerage.
Because margin involves borrowing, it also involves risk. Changes in market value or account conditions could affect how much you could trade and might require action if requirements are not met.
Understanding margin buying power helps you interpret the figures in your account and understand how margin trading works.
