This guide explains how F&O margin is calculated, why hedges reduce it, worked examples on Nifty, the order of placing legs, the expiry-day rules and the limits of the benefit.
How F&O margin is calculated
The margin for futures and options in India has two main parts:
- Initial margin (SPAN): the worst loss the portfolio could suffer in one day across a set of price and volatility scenarios.
- Exposure margin: an extra buffer set by the exchange as a share of the contract value.
Because the initial margin looks at the whole portfolio, positions that offset each other reduce it. A short call loses if Nifty rises; a bought call at a higher strike gains in the same scenarios, so the combined worst case is much smaller.
A worked example
Using Black–Scholes model prices with Nifty at 25,000, 12 days to expiry, IV of 14% and a lot of 65:
| Naked short call | Bear call spread | |
|---|---|---|
| Legs | Sell the 25,000 call at ₹280.50 | Sell the 25,000 call, buy the 25,500 call at ₹92.10 |
| Premium received | ₹18,233 | ₹12,246 |
| Maximum loss | Unlimited | ₹20,254 |
| Margin | High: SPAN and exposure on an open-ended risk | Much lower: the worst case is capped |
For the spread, the worst-case loss cannot exceed ₹20,254 per lot, so the initial margin is limited by that figure. The naked call's margin has no such cap and is many times larger. Exact margins depend on the exchange's parameters on the day; check them in your broker's margin calculator.
Common hedged structures
| Structure | Hedge | Margin effect |
|---|---|---|
| Bull put spread | A lower put against a short put | Large reduction |
| Bear call spread | A higher call against a short call | Large reduction |
| Iron condor | Wings on both sides of a short strangle | Large reduction |
| Iron fly | Wings on a short straddle | Large reduction |
| Futures with a bought option | A put against long futures, or a call against short | Reduction |
| Covered call on shares | Pledged shares as collateral | The shares count as collateral, not as a margin offset |
Place the hedge first
Brokers check margin when each order is placed. If you sell the option first, the broker blocks the full naked margin, and the order can be rejected if your account cannot cover it. Buy the hedge first, then sell the main leg, and the broker sees a hedged position from the start.
Many brokers and platforms place multi-leg orders in this order automatically. Check how yours handles baskets.
Expiry-day rules
SEBI's measures for index derivatives changed margins around expiry:
- Extra exposure margin: an additional 2% exposure margin applies to short index options on their expiry day.
- No calendar spread benefit on expiry day: from February 2025, positions in a contract expiring that day no longer get a margin offset against positions in other expiries.
- Upfront premium: option buyers must pay the full premium upfront.
A hedge in the same expiry still reduces the margin on expiry day. A hedge in a later expiry does not.
Intraday margin and peak snapshots
Clearing corporations check margins at random times during the day. Brokers must hold the full margin for your positions at each check, not just at the end of the day. If you remove a hedge during the day, the margin on the remaining naked leg applies at once.
The limits of the benefit
- The hedge must match. It must be on the same underlying. Different expiries get a smaller benefit, and none on expiry day.
- The benefit is not a reason to trade more. Lower margin lets you open more lots, but the maximum loss per lot is unchanged. Size by the maximum loss. See options risk management.
- Removing the hedge first is dangerous. When closing, close the short leg first, then the hedge, or close both together.
- Far, cheap hedges still help. Even a hedge several hundred points away caps the gap risk, though the margin saving is smaller than with a closer hedge.
Hedges and pledged collateral
Hedging reduces the margin needed. Pledged shares add to the margin available. At least half of the margin used must still be in cash or cash equivalents.
Hedged strategies in QuantPower
In QuantPower's strategy builder, set the bought legs to go first, and check the margin your broker shows before you deploy. The option profit calculator shows the maximum loss of the hedged position. See the F&O margin calculator for how margins are worked out.
Frequently asked questions
What is the hedge benefit in option trading?
The reduction in margin when a bought option offsets a short option on the same underlying and expiry, because the worst-case loss is capped.
How much margin do I save by hedging?
It depends on the strikes, the expiry and the exchange's parameters on the day. For close hedges the saving is large. Check your broker's margin calculator.
Do I get a hedge benefit on expiry day?
Yes, for hedges in the same expiry. The calendar spread benefit across expiries does not apply on expiry day, and an extra 2% exposure margin applies to short index options.
Why was my hedged order charged full margin?
The short leg was probably placed before the hedge. Place the bought leg first.
Does a hedge make option selling safe?
It caps the loss, which is the most important risk control, but the trade can still lose up to that cap.
Sources
- SEBI circular SEBI/HO/MRD/TPD-1/P/CIR/2024/132: Measures to strengthen the equity index derivatives framework, 1 Oct 2024
- NSE Clearing, risk management framework for equity derivatives (SPAN and exposure margin)
- SEBI circulars on collection of margins and peak margin snapshots, 2020–2021