Why Option Sellers Need Margin
- The Asymmetry of Risk: When you buy an option, your maximum loss is strictly limited to the premium you paid. But when you sell an option, your profit is limited to the premium received, while your potential loss is technically infinite.
- Exchange Protection: Because of this infinite risk, the NSE mandates that brokers collect a massive safety deposit (Margin) before allowing you to write an option. This ensures you can cover massive overnight gap up/down losses.
- SPAN vs Exposure Margin: The total margin is made of two parts. SPAN margin is calculated by the exchange's risk engine based on extreme market volatility scenarios. Exposure margin is an additional buffer (usually 2-3% of contract value) charged by the broker.