Initial Margin Explained: Collateral to Open Trades
By Ken Chigbo, Founder, KenMacro. Published 2026-05-13.
Quick answer
Initial margin is the portion of account equity a broker locks as collateral when a leveraged position is opened. It is calculated from position size, instrument, and leverage. Once the trade is live, the funds are reserved, not spent, and released when the position closes or partially closes.
What is initial margin?
Initial margin is the upfront collateral a broker requires before a leveraged position can be opened. It is expressed as a percentage of notional position size and is the direct mathematical inverse of leverage. At 30 to 1 leverage, initial margin is roughly 3.33 percent of notional value. At 500 to 1, it falls near 0.2 percent. The funds are not a fee or a cost, they are ring-fenced equity held against the position. Brokers display this amount as used margin in the platform, while the remainder of equity sits as free margin available for new trades or to absorb floating losses.
How traders use initial margin
Retail traders use initial margin to determine how many positions an account can carry simultaneously. Before opening a trade, the desk recommends calculating required margin as notional size divided by leverage, then comparing that figure to free margin. Institutional desks treat initial margin as a hard constraint on book construction, sizing each trade so total used margin sits well below equity to leave room for adverse moves before maintenance margin and stop-out levels trigger. Regulated brokers under ESMA, ASIC, and CFTC frameworks apply tiered initial margin requirements, with higher percentages on exotic pairs, indices, and crypto CFDs. Traders who ignore initial margin tend to overleverage early in a session, then run out of free margin when normal intraday volatility expands.
Worked example of initial margin
Consider a trader opening one standard lot of EUR/USD, notional 100,000 EUR, with an account offering 30 to 1 leverage. Initial margin equals 100,000 divided by 30, roughly 3,333 EUR, converted to account currency at the prevailing rate. If the account holds 10,000 USD equity, that single position consumes around a third of available collateral as used margin, leaving the remainder as free margin. Were the same position opened under 500 to 1 leverage offered offshore, initial margin would fall near 200 EUR, freeing capital but dramatically reducing the buffer before maintenance margin breaches force liquidation.
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Frequently asked
Is initial margin the same as a deposit or a fee?
No. Initial margin is neither a deposit nor a fee. It is account equity the broker reserves as collateral while a position is open. The funds remain the trader’s property and are released back to free margin when the position closes. Fees such as commissions, swaps, and spread are charged separately and do reduce equity. Confusing margin with cost is one of the most common mistakes new retail traders make when reviewing platform balance fields.
What is the difference between initial margin and maintenance margin?
Initial margin is the collateral required to open a position. Maintenance margin is the lower threshold equity must remain above to keep the position alive. When floating losses push equity below maintenance margin, the broker issues a margin call or, at stop-out level, force-closes positions. Initial margin is a one-time check at trade entry, while maintenance margin is monitored continuously throughout the life of the trade.
How is initial margin calculated on forex CFDs?
Initial margin equals the notional position size divided by the leverage ratio, then converted to account currency. For a 0.1 lot GBP/USD trade, notional is 10,000 GBP. At 30 to 1 leverage that produces 333 GBP of required margin. Brokers regulated under ESMA cap retail leverage on major pairs at 30 to 1, on minors and gold at 20 to 1, and apply lower caps to indices, commodities, and crypto CFDs.
Can initial margin requirements change after a position is open?
Yes. Brokers can raise margin requirements ahead of high-impact events such as central bank decisions, elections, or weekend gaps. When requirements rise, used margin recalculates against the new percentage, which can compress free margin sharply. Traders carrying large positions into known volatility windows should check the broker’s margin schedule in advance, since unexpected requirement changes have triggered margin calls on otherwise profitable books.
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