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To read an NSE futures-and-options contract correctly, work from the exact underlying and series, then verify five fields in the live exchange data: lot size, expiry, notional exposure, position-specific margin and open interest. A lot tells you how many units one contract controls; notional value measures that exposure; margin is collateral rather than the purchase price; expiry is the series’ final date; and open interest counts contracts that remain open. The examples below use India’s NSE equity-derivatives conventions. Other exchanges, asset classes and jurisdictions can use different multipliers, expiry days, settlement rules and margin models.
An illustrative contract line might read NIFTY 50 | 25,000 CE | weekly | expiry Tuesday. That line is not a live quote. Before trading, replace every illustrative value with the current NSE contract file, expiry calendar, settlement specification and margin shown for your position.
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What each field tells you at a glance
| Field | What it measures | What you must verify |
|---|---|---|
| Underlying | The index, share or other instrument whose price drives the contract. | Exact name, exchange and contract type. |
| Lot size (contract multiplier) | Units of the underlying represented by one contract. | Current NSE lot-size file; the exchange can change it. |
| Expiry | The scheduled final date for that futures or options series. | Weekly/monthly designation, holiday adjustment and settlement method. |
| Notional or contract value | Approximate underlying exposure represented by the position. | Current futures price or underlying level, multiplier and number of lots. |
| Margin | Collateral and risk resources required to open or carry a position. | Current position-specific calculation, option side and applicable components. |
| Open interest (OI) | Contracts that remain open at a particular series, normally reported in the exchange’s stated unit. | Exact expiry and strike, plus volume, spreads and market depth. |
These fields answer different questions. A larger lot changes the rupee exposure of every price movement, but it does not by itself tell you how much cash a broker will block. A high OI number shows participation in that series, not a guaranteed price direction.
How to confirm the lot size
Lot size means units per contract
Lot size is the number of shares or index units represented by one exchange-traded contract. If one contract has a multiplier of 50, one lot controls 50 units. Two lots control 100 units, and five lots control 250 units. Futures and options on the same individual security use the same permitted lot size for that underlying under NSE rules, subject to exchange revisions.
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NSE directs traders to its current F&O contract file for applicable lot sizes and quantity-freeze limits. Use that file for the exact symbol and series you intend to trade. Do not copy a lot figure from an old article, a historic contract note or a remembered example. Corporate actions, index methodology changes and exchange revisions can make an older multiplier wrong.
Calculate units before calculating money
- Identify the exact underlying and contract type.
- Read the current lot size in the NSE contract file.
- Multiply lot size by the number of lots in your order.
- Use that unit count in the exposure and payoff calculation.
For example, if a hypothetical contract file showed a lot size of 75 and you considered two lots, the position would represent 150 index units. The number 75 is used only to demonstrate arithmetic; it is not a current lot-size assertion for any particular contract.
Do not confuse lot size with quantity freeze
Lot size is the minimum contract quantity represented by one lot. A quantity-freeze limit is an exchange or risk-control limit on the number of contracts that can be placed in a single order or other specified order condition. They are separate fields. Read both from the current exchange file when planning a large order.
Notional exposure: the value your lots represent
Futures exposure
For a futures position, a practical notional calculation is:
futures price × lot size × number of contracts
Using a purely illustrative price of ₹25,000, a hypothetical lot size of 75 and one contract gives ₹1,875,000 of notional exposure (25,000 × 75). Two such contracts would represent ₹3,750,000. The calculation describes the underlying exposure; it is not a margin quote and does not predict profit or loss.
Actual futures profit and loss depends on the price change, multiplier, number of contracts, transaction costs and settlement. A one-point move with a 75-unit multiplier changes the contract’s gross value by ₹75 per lot before costs. Verify the exchange’s contract convention and tick value for the specific product.
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Bought-option exposure
A SEBI-filed educational document illustrates bought-option exposure as:
premium paid × lot size × number of contracts
With an illustrative premium of ₹120, a hypothetical lot size of 75 and one lot, the premium outlay would be ₹9,000 before charges (120 × 75). This is the amount paid for the option premium in the illustration, not a universal price or a statement about a live option. The buyer’s payoff also depends on strike, underlying price at exit or expiry, time value, volatility and costs.
Notional value is not cash required
A futures trader normally posts margin rather than paying the entire notional value up front. An option buyer generally pays the premium, while an option writer faces margin requirements that reflect the risk of the short position. Consequently, two contracts with the same notional exposure can require very different cash resources. Never infer the required funds by applying a remembered percentage to notional value.
How NSE margin works
Margin is collateral, not the contract’s price
NSE Clearing describes initial margin as a combination of risk components, including SPAN margin and other applicable requirements. Depending on the position and product, the calculation can include delivery margin, extreme loss margin (ELM) and margin on consolidated crystallized obligations. The amount can change as prices, volatility, expiry status, settlement obligations and the position itself change.
Your broker’s order screen is useful for the amount applicable to the order at that moment, but it is not a permanent promise. Check the margin again before carrying a position overnight, through expiry or after a large market move.
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The NSE Clearing margin page accessed on October 13, 2026 lists ELM rates of 2% of notional value for index derivatives and 3.5% of notional value for stock derivatives for the stated categories. Those are exchange rule parameters, not complete margin requirements. The same page sets out qualifications and exceptions, including special treatment for certain short-option cases. SPAN and other components can make the total requirement materially different from either percentage.
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Why the same lot can need different margin on different days
- Volatility: a higher risk estimate can increase SPAN requirements.
- Price and moneyness: changes in the underlying and option strike alter the risk profile.
- Time to expiry: requirements can change as the contract approaches settlement.
- Position side: a short option has obligations that a long option does not.
- Settlement status: delivery or crystallized obligations can add requirements.
- Portfolio offsets: permitted combinations may receive offsets, while concentrated risk may not.
Because these variables interact, a historical average or an example from an older SEBI-hosted document should not be used as today’s NSE requirement. Treat historical illustrations as education only and rely on the current exchange and broker calculation for an actual order.
Buyer, seller and delivery risk
An option buyer pays the premium and has a right, not an obligation, to buy or sell according to the contract. An option writer receives premium but assumes the corresponding obligation and normally faces margin requirements. For individual-stock options on NSE, the product specification states that the contracts are physically settled. A position held into settlement can therefore create delivery or receipt obligations in the underlying stock, subject to the current rules and broker procedures. Confirm whether your exact contract is cash- or physically settled and what action is required before expiry.
How to read expiry dates
Expiry belongs to the exact series
Expiry is the scheduled final date of one futures or options series. It is not simply “the end of the month.” A symbol can have weekly, monthly and longer-dated series, each with its own date. Read the expiry field together with the underlying, strike (for options), option type and settlement terms.
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NSE’s Nifty 50 specification currently lists weekly options expiring each Tuesday and monthly options expiring on the last Tuesday of the expiry month. These conventions are specific to the named NSE product and can be amended. Check the live instrument specification and exchange holiday calendar before placing an order.
NSE individual-stock example
NSE’s individual-stock F&O specification states a last-Tuesday expiry for the relevant series. If that Tuesday is a trading holiday, expiry moves to the preceding trading day. A holiday adjustment can therefore make the date earlier than a calendar reminder based on “last Tuesday.”
Expiry checklist
- Confirm the exchange and underlying.
- Identify whether the series is weekly, monthly or another tenor.
- Read the exact expiry date in the contract selector.
- Check the holiday calendar for an adjusted date.
- Verify cash versus physical settlement.
- Decide in advance how an open position will be closed, rolled or settled.
Do not extrapolate NSE Tuesday conventions to another exchange, commodity, currency or overseas index. Each market publishes its own calendar and settlement rules.
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What open interest tells you
OI counts positions that remain open
Open interest is the number of outstanding contracts in a particular series whose positions have not been closed, expired or otherwise removed under the exchange’s accounting. It is normally displayed for a defined expiry and, for options, a defined strike and call/put type. When one trader opens a long position and another opens a short position, aggregate OI increases by the corresponding contract count. When both sides close, OI decreases.
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Volume counts contracts traded during a period, such as a session. OI is a stock of open positions at a point in time. A contract can show high volume but modest OI if traders open and close positions quickly. Another contract can show large OI but little current volume if many positions are being held rather than actively traded.
| Observation | What it can indicate | What it cannot prove |
|---|---|---|
| High OI | Many contracts remain open; the series may have established participation. | That price will rise or fall, or that execution will be easy. |
| Rising OI with rising volume | New positions may be entering as activity increases. | Whether those positions are predominantly bullish or bearish. |
| Falling OI | Positions may be closing, expiring or shifting to another series. | Whether traders are taking profit, cutting losses or rolling. |
| High OI but wide spread | Participation exists, but executable liquidity may still be poor. | That the quoted OI is available at one tradable price. |
Price-and-OI combinations are often used as heuristics, but they are not a directional signal by themselves. A long and a short exist for every open contract, and aggregate OI does not reveal which side has the stronger conviction. Combine OI with traded volume, bid/ask spread, displayed depth, implied volatility, time to expiry and your intended order size.
Why the exchange monitors OI
NSE uses aggregate open interest in market-wide monitoring and position-limit processes. When specified thresholds are breached, rules can restrict participants to closing trades. OI also appears in exchange provisions concerning whether particular option strikes remain available. These regulatory uses are different from interpreting OI as a forecast.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to compare two futures or options contracts
When two series are genuine alternatives, compare the same fields in the same order. A contract with a lower premium is not automatically cheaper in risk terms, and a contract with larger OI is not automatically easier to execute.
| Comparison | Questions to answer | Why it matters |
|---|---|---|
| Underlying and multiplier | What instrument is exposed, and how many units does one lot represent? | Determines sensitivity to each price move and total units. |
| Expiry and time remaining | Is it weekly, monthly or longer-dated? Is a holiday adjustment involved? | Changes time value, roll decisions and settlement timing. |
| Notional exposure | What is price or index level × lot size × lots? | Shows the scale of exposure before considering margin. |
| Margin and settlement | What does the current calculator require for this side and portfolio? Is settlement cash or physical? | Determines funding needs and operational obligations. |
| Liquidity | What are OI, recent volume, bid/ask spread and depth for this exact series? | Affects entry, exit and slippage. |
Write down the values from the same timestamp when comparing contracts. OI and volume can change during the session, while margin can change after a risk-parameter update or market move.
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A practical reading sequence before placing an order
- Select the exact contract: choose the exchange, underlying, futures or options type, strike (if applicable) and expiry.
- Open the current specification: confirm lot size, quantity-freeze information, tick convention and settlement method.
- Compute units: multiply lot size by intended lots.
- Estimate notional exposure: use the current futures price or underlying level and the exchange multiplier.
- Check live margin: enter the exact position in the broker or exchange-linked calculator; note SPAN, ELM, delivery and other components where shown.
- Inspect liquidity: review OI, session volume, spread and depth for the exact strike and expiry rather than the underlying symbol generally.
- Check expiry operations: confirm the calendar date, holiday adjustment, last trading time and physical-delivery procedure where applicable.
- Set risk limits: decide the maximum loss, exit condition and funds reserved for changing margin or settlement obligations.
- Recheck before submission: verify that the order quantity is in lots, the expiry is correct and the displayed margin is for the intended buy or sell side.
Common reading mistakes and fixes
Using an old lot size
Symptom: your calculated exposure does not match the broker’s contract value. Fix: download the current NSE contract file and recalculate units, notional value and tick impact.
Treating margin as a down payment
Symptom: a percentage of notional is assumed to be the final cash requirement. Fix: use the position-specific margin display and include possible delivery, ELM and crystallized-obligation components.
Assuming every “monthly” contract expires on the same date
Symptom: a calendar reminder points to a holiday or the wrong product. Fix: read the exact series specification and apply the exchange holiday rule.
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Reading OI as bullish or bearish proof
Symptom: a trade is justified solely by rising OI. Fix: pair OI with volume, spread, depth, price context and a defined risk plan; OI alone does not identify direction.
Ignoring physical settlement
Symptom: a stock option is held into expiry without the ability or intention to deliver or receive shares. Fix: verify the current physical-settlement process and close or manage the position before the broker’s stated deadline if delivery is unsuitable.
What is established, and what must stay current
The NSE contract and margin pages accessed on October 13, 2026 provide the applicable specifications at that time, but live values can change. The current lot-size file, holiday calendar, margin parameters, strike availability and OI figures should be checked immediately before a trade. A July 2024 SEBI consultation paper discusses expiry-related activity, open positions and volatility in a proposal context; it is not, by itself, a binding replacement for later exchange or regulatory rules. A November 2023 SEBI-hosted scheme document contains historical educational examples, so its figures should not be used as present-day NSE margin guidance.
Quick Recap
Final pre-trade checklist
- Current lot size and quantity-freeze limit from the NSE contract file.
- Exact expiry date, including a Tuesday-holiday adjustment where applicable.
- Cash or physical settlement and the operational deadline.
- Notional exposure based on the current price, multiplier and number of lots.
- Live margin for the exact portfolio, side and expiry, not a remembered percentage.
- Open interest, recent volume, bid/ask spread and depth for the exact series.
- A plan for changing margin, expiry settlement and maximum acceptable loss.
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