Margin Requirements & Capital Rules

Margin is security the exchange system holds against your obligations. It is not a price paid, and it is not a cap on loss.

Say your account has ₹2,50,000 and the broker shows ₹1,31,850 blocked against a NIFTY futures position. You have not spent ₹1,31,850 buying the index. The block secures the contract, while the price exposure and settlement obligations stay with you.

Who is protected? NSE Clearing stands between clearing members as the central counterparty, and your broker collects the required resources from you. The system keeps clearing orderly. It does not guarantee your result, and it cannot promise that collateral covers every possible move.

SPAN is a scenario test of your whole portfolio. It asks how much you could lose under a set of stressed moves, and asks for security against that.

The name stands for Standard Portfolio Analysis of Risk. It does not apply one fixed percentage to every contract. It revalues your positions under prescribed changes in the underlying price and in volatility. A protective option can offset part of another position’s scenario loss. Minimum requirements and portfolio adjustments also apply, so SPAN is not your stop-loss distance.

NSE Clearing describes initial margin using a 99% value-at-risk framework over the applicable risk horizon, with two-day treatment for specified futures circumstances where overnight MTM collection cannot be completed before the next trading session. Therefore, “the largest one-day loss” is an incomplete description, and no risk model establishes the maximum loss a trader can experience.

Two clocks run side by side. Clearing refreshes its margin parameters during the day and at its end. Checks on whether clients paid their margin upfront use fixed beginning-of-day parameters and intraday snapshots, including net option premium payable. So an unchanged trade can need more support later in the day. A sampled figure does not promise that the live requirement stays put.

Before you trust a basket total, check the underlying, expiry, strikes, quantities, completed fills and the time of the figure. A protective leg that has not been filled is not a hedge. SPAN works on your own portfolio; other clients’ positions are never netted against yours.

Extreme Loss Margin, or ELM, is a second security layer added on top of SPAN. Your app may call it “exposure margin”. The ordinary NSE rates are 2% of index notional and 3.5% of stock notional. These are baseline rates. They are not the total margin percentage of any portfolio.

For futures, the relevant notional uses the futures contract price and quantity. For a short option, it uses the previous available underlying reference and the equivalent quantity, rather than the option premium. In our constructed NIFTY reference of 24,500 points and 65 assumed units, the notional is ₹15,92,500 and ordinary 2% ELM is ₹31,850. A ₹100 option premium is not this calculation’s base.

Special rates can apply. NCL lists 3% for short index options more than 10% out of the money, and 5% for short index options with more than nine months remaining. Short stock options more than 30% out of the money carry 5.25%. The relevant out-of-the-money tests use the specified previous underlying close. Check the selected contract and current circular instead of treating 2% as universal.

Expiring short index options attract an additional 2% ELM on expiry day, including qualifying positions opened that day. This particular add-on does not apply indiscriminately to all futures, bought options or short stock options. A stock position has its own delivery and other margin framework.

The total can include SPAN, ELM, delivery margin, margin on crystallised obligations and other additions. A crystallised obligation is a payment already fixed by executed trades: a net premium payable, or the loss on a closed future. Each part has its own purpose, so keep the security requirement, the cash payment and the account balance apart.

To see the expiry effect alone, take one short NIFTY index option, with the same 24,500 reference and 65 units. Give it an invented SPAN output of ₹1,00,000. Ordinary ELM of ₹31,850 brings the stack to ₹1,31,850. On expiry day another ₹31,850 is added, so the stack is ₹1,63,700. These are teaching inputs, not an exchange quote.

A buyer of one NIFTY option pays its premium, and that is the whole entry payment. The buyer does not post the SPAN and ELM security that an uncovered writer must. But “buyers never need margin” goes too far. An in-the-money stock option close to physical settlement can attract delivery margin and a large cash or share obligation.

Since 10 February 2025, NSE Clearing collects net option premium payable upfront. It followed a 9 January 2025 circular; SEBI’s original date was 1 February, so the later date is the one that applied in practice. For our one-leg purchase, ₹100 × 65 units means ₹6,500 payable upfront. Your broker’s funding rules still apply.

A pledge lets shares you own count as margin while they stay in your demat account. Margin, leverage and pledging shows the steps and a real haircut. For F&O the idea is the same: you authorise the pledge, the clearing corporation values it after a haircut, and the support flows through your broker to the clearing member. Pledging does not sell the shares or create cash.

Take an approved holding worth ₹1,50,000 and assume a 20% haircut. The haircut is ₹30,000, so ₹1,20,000 counts as support. The ₹30,000 is not a loss; the shares are still yours. A later price fall or a higher haircut can lower the credited support without any sale.

A hedge cuts margin because it cuts measured risk, not because two orders earn a discount. Take one separate same-expiry NIFTY case: sell the 25,000 Call at ₹100 and buy the 25,200 Call at ₹40, 65 units. The net credit is ₹60 a unit, so ₹3,900 received. At expiry this bear call spread loses at most (200 − 60) × 65 = ₹9,100 before costs.

The bought Call gains value in the rising markets that hurt the short Call, so the risk model can recognise the offset. How much margin that saves depends on your actual legs and the current rules. ₹9,100 is the loss cap at expiry. It is not a margin quote, a minimum deposit or a limit on delivery funding for a stock option.

Three things can open a gap without a new trade: cash falls, recognised collateral shrinks, and the requirement rises. Here they are in one account. It starts with ₹80,000 cash and ₹1,20,000 recognised collateral against a ₹1,50,000 requirement. Then a ₹20,000 cash loss leaves ₹60,000, collateral drops ₹30,000 to ₹90,000, and the requirement rises to ₹1,70,000. Support is ₹1,50,000, so the gap is ₹20,000.

The ₹20,000 gap is not a second trading loss. It is the distance between what you hold and what is required at that moment. A real account may also owe cash components this simple ledger leaves out, and a positive collateral total does not prove a cash payment is covered.