Portfolio Margin

Portfolio margin is a risk-based margin system that calculates margin requirements based on the overall risk of your entire portfolio rather than applying fixed percentages to individual positions. Using a theoretical pricing model (typically OCC's TIMS — Theoretical Intermarket Margin System), portfolio margin evaluates how your portfolio would perform across a range of market scenarios. The result is typically 3x to 6x more buying power than Regulation T margin.

Why It Matters

Portfolio margin dramatically increases capital efficiency for hedged or diversified portfolios. Under Reg T, a protective put and its underlying stock are margined separately — the system does not recognize that the put offsets the stock's downside risk. Portfolio margin sees the combined position and requires margin only for the net risk. This means traders who hedge their positions or run diversified strategies can put on more positions with the same capital.

However, more buying power means more potential risk. Portfolio margin accounts can accumulate larger positions, which amplifies both gains and losses. The reduced margin is a tool — it does not reduce risk. It gives experienced traders the flexibility to deploy capital more efficiently, but it requires disciplined risk management.

How It Works

How portfolio margin is calculated: The OCC's TIMS model simulates how your portfolio would perform under a range of stock price and volatility scenarios. Typically:

• Stock prices are moved up and down by a percentage (usually +/- 15% for broad-based indexes, +/- 8-10% for individual stocks)
• The worst-case portfolio loss across all scenarios becomes your margin requirement

Eligibility requirements:

• Minimum account equity of $125,000 (some brokers require more)
• Approval for higher-level options trading (typically Level 4 or above)
• Demonstrated experience and knowledge of options and margin
• Your broker must offer portfolio margin (most major brokers do)

Portfolio margin vs. Reg T examples:

Key benefits:

• Recognizes hedging: long stock + short call, or long stock + long put, are margined as a combined position
• Recognizes diversification: positions across uncorrelated stocks offset each other
• More efficient use of capital for complex multi-leg strategies
• Lower margin on index products and broad-based ETFs

Key risks:

• Leveraged losses can exceed your account equity
• Margin requirements change in real-time and can spike during market stress
• A VIX spike can increase margin requirements across your entire portfolio simultaneously
• Brokers can increase margin requirements (house margin) at any time
• Concentration risk: large positions in a single stock will have high margin regardless

Portfolio margin stress: During market crashes, portfolio margin requirements can spike dramatically as the model projects larger losses. This can create margin calls at the worst possible time — when markets are already dropping. Maintaining a significant cash buffer (30-50% of buying power) is essential.

Quick Example

You have a $200,000 portfolio margin account. Under Reg T, selling 10 naked $190 puts on a $200 stock would require $34,000 in margin. Under portfolio margin, the same position might require only $12,000 — freeing up $22,000 for other trades.

You use the extra buying power to add a hedged stock position and an iron condor on a different stock. Your total portfolio margin is $45,000, leaving $155,000 in excess equity. Under Reg T, the same positions would require $120,000, leaving only $80,000 in excess.

But when the market drops 5% in a day, your portfolio margin increases from $45,000 to $85,000 because the model now projects larger potential losses. Your excess equity drops to $115,000. A further 5% drop might push margin to $130,000. If your portfolio losses bring equity below the margin requirement, you face a margin call.