Portfolio Margin
A risk-based margin framework that nets exposure across all your F&O positions so genuinely hedged books attract lower combined capital requirements.
Definition
Portfolio margin is a methodology that calculates margin requirements by assessing the net risk of your entire open book rather than treating each leg or contract independently. NSE and BSE implement this through the SPAN (Standard Portfolio Analysis of Risk) engine, which simulates a range of price and volatility scenarios and sets margin equal to the worst projected loss across that whole portfolio. A protective put against a futures long, for instance, reduces the SPAN margin compared with holding each position in isolation, because the exchange recognises the hedge offsets part of the downside risk.
Why it matters
For traders who build structured positions — iron condors, calendar spreads, or delta-neutral portfolios — portfolio margin unlocks materially lower capital deployment compared with flat per-leg addition. This efficiency directly translates into better capital utilisation: you can hold the same hedged position with less collateral blocked, leaving more free margin to absorb intraday MTM swings or add to other instruments. Conversely, a naked short strangle on Bank Nifty will attract nearly the full SPAN margin on both legs because there is no opposing position to net against. Understanding how SEBI-mandated SPAN offsets work helps you structure trades that are capital-efficient without adding hidden tail risk.
How it works
SPAN divides margin calculation into two layers. First, it runs sixteen price-volatility scenarios — typically covering moves of roughly ±3 standard deviations and volatility shifts of ±25% — and computes the portfolio P&L under each. The scenario producing the largest loss becomes the SPAN margin. Second, brokers add an exposure margin on top as a further buffer. When you add a hedging leg that profits in the scenarios where the existing position loses, SPAN reduces the worst-case figure, and your total margin requirement falls. The saving is known as a margin benefit or inter-contract spread credit.
Example
Suppose you sell one lot of Nifty futures (hypothetical lot size 25) and simultaneously buy one at-the-money put on the same expiry. In isolation, the short future might attract a SPAN margin of around Rs 80,000. But the long put profits if Nifty falls sharply — the same scenario that hurts the short future — so the SPAN engine recognises the partial hedge. The combined SPAN margin might drop to roughly Rs 30,000–40,000, with the exact offset depending on the put's strike, days to expiry, and the prevailing implied volatility. This is the core mechanic of portfolio margining at work.
Build smarter, margin-efficient positions
Check live open interest and option chain data on TradePulse before structuring multi-leg trades.