Margin Requirements

Margin requirements are the amount of capital your broker requires you to have in your account to open and maintain an options position. For buyers, the requirement is simply the premium paid. For sellers, the requirement depends on the strategy — defined-risk strategies require less margin than undefined-risk (naked) positions because the maximum loss is capped.

Why It Matters

Margin determines your capital efficiency — how many positions you can have open simultaneously and how much of your account each trade uses. Understanding margin lets you plan position sizes, avoid margin calls, and select strategies that fit your account size.

A margin call occurs when your account equity falls below the maintenance requirement. Your broker will force you to either deposit more funds or close positions — often at the worst possible time. Knowing your margin requirements in advance prevents this scenario.

How It Works

Margin for buyers (long options):

• You pay the full premium upfront
• No additional margin required
• Maximum loss = premium paid
• Example: Buy 1 call at $3.00 = $300 required

Margin for defined-risk sellers (spreads):

• Required margin = width of the spread minus credit received
• Example: Sell a $5-wide put spread for $1.50 credit
  • Margin = $5.00 - $1.50 = $3.50 per share ($350 per contract)
  • This is also your maximum loss

Margin for naked puts: The standard formula (varies by broker):

Greater of: (20% of underlying price - OTM amount + premium) or (10% of strike price + premium)

• Example: Stock at $100, sell $95 put for $2.00
  • 20% of $100 = $20, minus $5 OTM = $15, plus $2 premium = $17.00
  • 10% of $95 = $9.50, plus $2 premium = $11.50
  • Margin = $17.00 per share ($1,700 per contract)

Margin for naked calls: Similar formula but with unlimited theoretical risk, so margin is typically higher:

Greater of: (20% of underlying price + premium - OTM amount) or (10% of underlying price + premium)

Portfolio margin: Available to accounts over $125,000 (at most brokers). Uses a risk-based model that calculates margin based on the overall portfolio's risk, not individual positions. Portfolio margin can reduce requirements by 50-75% for well-diversified options portfolios.

Key margin concepts:

• Initial margin: Required to open a position
• Maintenance margin: Required to keep a position open (usually the same or slightly less)
• Buying power: Your account equity available for new trades after existing margin is accounted for
• Margin call: When account equity drops below maintenance — you must add funds or close positions

Quick Example

You have a $25,000 account. You want to sell iron condors on SPY ($5-wide wings, collecting $1.00 credit each).

Margin per condor: $5.00 - $1.00 = $4.00 per share = $400 per condor. With $25,000, you could theoretically open 62 condors — but prudent risk management would limit you to 5-10 positions ($2,000-$4,000 in margin) to leave room for adjustments and avoid a margin call if the market moves.