Margin & Leverage: The Double-Edged Sword
Lesson 4: Margin & Leverage
Margin is how retail traders punch above their weight — and how they get absolutely destroyed. It's the double-edged sword that makes options the most dangerous game in finance.
What is Margin?
Margin is a loan from your broker secured by the assets in your account. There are two key concepts:
1. Buying on Margin (Leverage)
You deposit $10,000. Your broker lets you buy up to $20,000 worth of stock (2:1 leverage for equities under Reg T). You borrow the other $10,000 and pay interest on it.
Example: You use $20,000 to buy 200 shares of a $100 stock with $10,000 of your own money + $10,000 borrowed. If the stock goes to $120, your position is worth $24,000. After repaying the $10,000 loan, your equity is $14,000 — a 40% return on your $10,000 instead of 20%. But if it drops to $80, your position is worth $16,000. After repaying $10,000, you have $6,000 — a −40% loss instead of −20%.
2. Initial Margin vs. Maintenance Margin
| Term | Definition | Reg T Standard |
|---|---|---|
| Initial Margin | Minimum equity required to open a position | 50% of purchase price |
| Maintenance Margin | Minimum equity you must maintain in your account | 25% (brokers can set higher — usually 30%) |
| Margin Call | Broker demands more money or liquidates your positions | Triggered below maintenance |
Options Margin Requirements
Options margin is different from stock margin. Here's what matters:
| Option Position | Margin Required |
|---|---|
| Long calls/puts (buying) | Premium paid only — no additional margin. Max loss is defined. |
| Naked short call | Massive. Formula: Premium + max(20% of underlying − OTM amount, 10% of underlying). Potentially unlimited loss. |
| Naked short put | Premium + max(20% of underlying − OTM amount, 10% of underlying). Loss capped at strike × 100. |
| Covered call | None beyond owning the shares. Shares serve as collateral. |
| Cash-secured put | Cash equal to strike × 100 must be held. No leverage. |
| Spread (defined risk) | Width of the spread × 100. Defined and known upfront. |
Pattern Day Trader (PDT) Rule
If you make 4+ day trades in a 5-day rolling period in a margin account, you're flagged as a Pattern Day Trader and must maintain at least $25,000 in equity. Drop below that and you're restricted to closing positions only. This is a FINRA rule, not a broker policy.
Buying Power and Leverage Ratios
Options buying power reduction depends on the position type, not a fixed ratio like stock margin:
- Long options: 100% of premium (no leverage)
- Defined-risk spreads: Max loss × 100 (still defined)
- Naked options: 10-20% of underlying equivalent (massive leverage)
The key insight: buying options is cash-only (you can't lose more than you paid), but selling options unleashes margin leverage. This is why WSB loss porn almost always involves selling options or using portfolio margin.
Portfolio Margin
For accounts over $125,000, brokers may offer portfolio margin instead of Reg T. This uses risk-based calculations: a diversified portfolio of offsetting positions requires far less margin than individual positions. It can boost leverage to 6:1 or higher — and make blow-ups that much more spectacular.
Real WSB Math: The $50K → $0 Speedrun
You deposit $50,000. You sell 10 naked puts on a $50 stock, collecting $2.00 each ($2,000 total premium). Margin requirement: ~$10,000 per contract = $100,000 total. You need portfolio margin to even open this.
Stock drops to $35. Each put is $15 ITM = $15,000 loss per contract × 10 = $150,000 loss. After subtracting the $2,000 premium and your $50,000 deposit... you owe your broker $98,000.
This is not hypothetical. This happens every time there's a sharp selloff.
🧠 Knowledge Check
1. What is the maximum loss on a LONG call option?
2. The Pattern Day Trader rule triggers at how many day trades in a 5-day period?
3. Which position has the LEAST margin required?