Margin and Leverage
Explained
Margin is the deposit that lets you control a large derivatives position with less capital. Leverage amplifies both gains and losses — understanding how it is calculated and how it changes is essential before you write a single option.
What is margin in derivatives?
When you buy an option, your maximum loss is the premium you pay — so no additional margin is needed beyond that upfront cost. But when you sell (write) an option or trade futures, your potential loss can be much larger. The exchange therefore requires you to set aside a margin deposit before the trade is accepted. This deposit stays blocked in your account as long as the position is open, and it moves up or down daily based on market conditions.
SPAN margin: the core calculation
SPAN margin (Standard Portfolio Analysis of Risk) is the primary margin component for futures and short options on NSE. It is calculated by the SPAN algorithm — developed by the Chicago Mercantile Exchange and adopted by most exchanges worldwide — which simulates your portfolio across 16 different combinations of price moves and volatility changes. The worst-case loss across those scenarios becomes your SPAN margin requirement.
SPAN margin is dynamic. When India VIX spikes — for example, during pre-election uncertainty or a global sell-off — SPAN margins for NIFTY futures and short options increase automatically because the exchange's worst-case simulations now include larger potential moves. Conversely, in calm low-VIX environments, SPAN margins compress. Traders who do not monitor margin in real time can find themselves hit by an unexpected shortfall on a high-VIX day even without an adverse trade move.
Exposure margin: the second component
On top of SPAN, NSE collects an exposure margin (also called extreme loss margin or additional margin). This is a fixed percentage of the contract's notional value and acts as a buffer for losses beyond the SPAN scenario. For most index futures and options, exposure margin is 3% of notional value. Total margin = SPAN + exposure margin.
How leverage works: a clear definition
Leverage is the ratio of the position's notional value to the capital you deploy. If NIFTY is at 23,000 and one futures lot is 75 units, one lot controls a notional value of 23,000 × 75 = ₹17,25,000. If the margin required is ₹1,20,000, the leverage is ₹17,25,000 ÷ ₹1,20,000 = approximately 14x.
This means a 1% adverse move in NIFTY (₹230 per unit) translates into a mark-to-market loss of ₹230 × 75 = ₹17,250 — which is 14.4% of your ₹1,20,000 margin. Leverage amplifies losses at the same rate it amplifies profits.
A worked NIFTY example (hypothetical)
Suppose NIFTY is trading near 23,500 (hypothetical) and you sell one lot of the 23,700 call (an OTM strike) at a premium of ₹80 per unit. Gross premium received = ₹80 × 75 = ₹6,000. However, to hold this short call, your broker collects, say, ₹85,000 in SPAN margin + ₹52,000 in exposure margin = ₹1,37,000 total margin blocked.
Your effective return if the option expires worthless: ₹6,000 on ₹1,37,000 deployed = 4.4% for the week. Looks attractive — but if NIFTY rallies 400 points by expiry, your loss on the short call is (₹200 intrinsic - ₹80 premium received) × 75 = ₹9,000, not counting charges. Your margin deposit did not shrink your risk — it simply ensured the exchange could cover your potential obligation.
Mark-to-market (MTM) settlement
Futures positions are settled mark-to-market daily in India. If you hold a long NIFTY future and it falls 100 points overnight, ₹100 × 75 = ₹7,500 is debited from your account the next morning. You must have sufficient funds to absorb these daily debits. MTM does not apply to bought options (which are settled on exercise/expiry) but does affect futures and the margin account that backs short options.
Portfolio margin: the offset benefit
If you hold offsetting positions — for example, a short strangle (short call + short put) rather than a naked short call — the SPAN system recognises that your positions partially offset each other's risk and reduces the combined margin accordingly. This is why structured strategies like iron condors require significantly less margin than the sum of two naked short positions. Use the margin calculator on TradePulse or your broker platform to see the precise offset before entering any multi-leg strategy.
Common mistakes
- Treating margin as the cost of the trade. Margin is a performance deposit, not a fee. It is returned when you close the position. Confusing margin with cost leads to miscalculating your actual capital utilisation.
- Holding positions into a VIX spike without a buffer. If you use 90–100% of your available capital as margin, a VIX spike that raises margins will force a square-off at the worst possible moment. Always maintain a 30–40% margin buffer.
- Adding to a losing leveraged position. Leverage means losses compound quickly. Adding to a losing futures or short options trade to "average down" can wipe out an account before the market reverses.
- Ignoring overnight gap risk on naked shorts. Futures and naked short options carry overnight gap risk that SPAN margin does not fully protect against. Always know the worst-case loss on your position if the market opens 3–5% against you.
Frequently asked questions
What is SPAN margin?
SPAN margin is the minimum deposit required by NSE to carry a futures or short options position, calculated by simulating worst-case portfolio moves across 16 price-and-volatility scenarios overnight. It rises when India VIX increases and falls in calm conditions.
Do option buyers need to pay margin?
No. Option buyers pay the full premium upfront and that is their maximum loss — no further margin is required. Margin requirements apply only to option sellers and futures traders whose potential losses can exceed the initial premium received.
What happens during a margin call?
If your account balance falls below the required margin level — due to MTM losses or a VIX-driven margin increase — your broker will issue a margin call. If you do not deposit additional funds promptly, the broker may square off your position at an unfavourable price to limit their own exposure.
What is the difference between initial and maintenance margin?
Initial margin is the amount required to open a position. Maintenance margin is the minimum balance needed to keep it open. SEBI requires full initial margin upfront in India. If MTM losses erode your balance below maintenance levels, a margin call is triggered.
Monitor your margin in real time
TradePulse shows live NIFTY option chain data, open interest, and Greeks — the inputs that drive your margin requirements every day.