Where do I check today's F&O lot size, expiry day and margin on NSE?
The exact NSE pages and files to open, what each one tells you, and why the money needed to buy an option differs from the money needed to sell one.
Published 3 November 2026 · Potoos Research Services
Check NSE's own files, not an old screenshot. Lot sizes are in NSE's "Permitted lot size" file on its Equity Derivatives Contract Information page, with one column per expiry month. The expiry day is on NSE's Contract Specifications page: Tuesday for its index and stock derivatives, or the previous trading day if Tuesday is a holiday. Margin depends on the position. Option buyers pay the premium upfront. Option sellers post margin, which your broker collects under NSE Clearing's rules.
Why an old screenshot goes wrong
Lot sizes and expiry days change. SEBI's circular of 1 October 2024 says an index derivative contract must be worth "not less than Rs. 15 lakhs" when introduced, and the lot size is fixed so that the contract value "on the day of review is within Rs. 15 lakhs to Rs. 20 lakhs". Prices move, so lot sizes are reviewed. Expiry days have changed as well. NSE's circular NSE/FAOP/68747 of 25 June 2025 moved NIFTY weekly contracts from Thursday to Tuesday, and monthly index and stock contracts from the last Thursday to the last Tuesday, for contracts expiring on or after 1 September 2025.
A screenshot shows what was true on the day it was taken. The exchange file shows what is true today.
Where NSE publishes the lot size
NSE's Equity Derivatives Contract Information page has a link called "Permitted lot size (.csv)". It opens a spreadsheet file. Each row is one underlying, an index or a stock, with its symbol. Each column after that is an expiry month, written like NOV-26 or DEC-26. The number where your row meets your expiry month is the lot size for that contract.
The same page also links NSE's "Quantity Freeze (.csv)" file and its stock options strike scheme.
Where NSE publishes the expiry day
NSE's Contract Specifications page states it in the "Expiry Day" row:
- For Nifty 50, Nifty Bank, Nifty Financial Services, Nifty Midcap Select, Nifty Next 50 and Nifty India FPI 150: "Tuesday of the expiry period. If the Tuesday is a trading holiday, then the expiry day is the previous trading day."
- For individual securities: "Tuesday of the expiry period. If the last Tuesday is a trading holiday, then the expiry day is the previous trading day."
The same page gives the trading cycle. Nifty 50 options have "4 weekly expiration contracts (excluding monthly contracts) and 3 monthly expiration contracts". The other five indices have 3 monthly expiration contracts. Nifty 50 and Nifty Bank options also have quarterly expiries, and Nifty 50 has longer-dated half-yearly ones.
Why buying an option needs a different amount from selling one
Buying an option. You pay the premium. SEBI's 1 October 2024 circular made brokers collect "options premium upfront from option buyers", from 1 February 2025.
Selling an option, or holding futures. You post margin. NSE Clearing's margins page says it collects initial margin up front for open positions using SPAN, a portfolio-based system, and that a trading member "should collect upfront margins from his clients". Initial margin is based on "99% value at risk over a one day time horizon". On top of that is the extreme loss margin. For a short options contract it is worked out on "the value of underlying index or the value of an equivalent number of underlying shares".
That is why the two sides need different amounts. The buyer's cost is the premium. The seller's margin is sized to the risk of the underlying moving against the position.
Why the margin can rise near expiry
NSE Clearing's margins page names one reason directly: "On the day of options contracts expiry, an additional extreme loss margin of 2% shall be levied on short index options contracts." Its list of what makes up initial margin also includes delivery margins. For the exact amount on your own position, ask your broker. It is the one collecting it.
Index options settle in cash. Stock F&O can end in delivery.
NSE Clearing's settlement mechanism page says index options are European style, "Final Exercise is Automatic on expiry", and exercise settlement is in cash. For option contracts on an index, the final settlement amount is paid on T+1, the day after expiry.
Stock derivatives are different. NSE's circular NSE/INSP/47293 of 10 February 2021 says "physical settlement shall be mandatory for all stock derivatives with effect from October 2019 expiry onwards." Physical settlement means delivery of the shares. The same circular says brokers must make physical settlement available to clients "without having any default option of mandatory/automated squaring off the positions", and must tell clients about the risk measures in their own policies. So read your broker's policy on physical settlement before you keep a stock future or a stock option open into expiry.
Both kinds of contract stop existing after expiry. NSE Clearing says open positions in option contracts "cease to exist after their expiration day".
This page is published by Potoos Research Services, a SEBI-registered Research Analyst, registration INH000027380, Chennai. We do not copy lot sizes onto this page because they change. Always read the number from NSE's file on the day you need it.
How to check this yourself
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Open NSE's contract information page
Tap this link to NSE's Equity Derivatives Contract Information page. It opens on nseindia.com.
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Open the lot size file
Scroll down to "Permitted lot size (.csv)" and tap it. On a phone it downloads a file. Open it with a spreadsheet app, or tap the file link directly.
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Find your row and column
Find the row for your index or stock symbol. Move across to the column for your expiry month. That number is the lot size.
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Check the expiry day
Tap NSE's Contract Specifications page and scroll to the table. Read the "Expiry Day" row. If that Tuesday is a trading holiday, expiry moves to the trading day before it.
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Ask your broker for margin and delivery rules
Margin is collected by your broker, so its order screen or support desk gives the amount for your position. Ask for its physical settlement policy too if you trade stock futures or stock options.
Sources
- NSE, Equity Derivatives Contract Information, links "Permitted lot size (.csv)" and "Quantity Freeze (.csv)": https://www.nseindia.com/static/products-services/equity-derivatives-contract-information
- NSE, Permitted lot size file (fo_mktlots.csv), columns NOV-26 onwards, downloaded 3 November 2026: https://nsearchives.nseindia.com/content/fo/fo_mktlots.csv
- NSE, Equity Derivatives Contract Specifications, Trading Cycle and Expiry Day rows (page updated 11 August 2026): https://www.nseindia.com/static/products-services/equity-derivatives-contract-specifications
- NSE circular NSE/FAOP/68747 (Circular Ref. No. 111/2025), 25 June 2025, Revision in Expiry Day of Index and Stock Derivatives Contracts - Update: https://nsearchives.nseindia.com/web/sites/default/files/inline-files/FAOP68747.pdf
- SEBI, Measures to Strengthen Equity Index Derivatives Framework, SEBI/HO/MRD/TPD-1/P/CIR/2024/132, 1 October 2024 (PDF: https://www.sebi.gov.in/sebi_data/attachdocs/oct-2024/1727786261636.pdf), paras 5.1 and 5.4: https://www.sebi.gov.in/legal/circulars/oct-2024/measures-to-strengthen-equity-index-derivatives-framework-for-increased-investor-protection-and-market-stability_87208.html
- NSE Clearing, Equity Derivatives Margins: https://www.nseclearing.in/risk-management/equity-derivatives/margins
- NSE Clearing, Equity Derivatives Settlement Mechanism: https://www.nseclearing.in/clearing-settlement/equity-derivatives/settlement-mechanism
- NSE circular NSE/INSP/47293 (Circular Ref. No. 08/2021), 10 February 2021, Physical settlement of stock derivatives: https://nsearchives.nseindia.com/content/circulars/INSP47293.pdf
Checked on 3 November 2026
Common questions
Where do I find today's F&O lot size on NSE?
On NSE's Equity Derivatives Contract Information page, in the file called "Permitted lot size (.csv)". Each row is an index or stock, and each column is an expiry month. Read the number on the day you need it, because lot sizes are reviewed and change.
What day do NSE index and stock derivatives expire?
NSE's Contract Specifications page says Tuesday of the expiry period for its index derivatives and for individual securities. If that Tuesday is a trading holiday, the expiry day is the previous trading day.
Why does buying an option need a different amount of money from selling one?
An option buyer pays the premium, and SEBI made brokers collect it upfront from 1 February 2025. An option seller posts margin, made of SPAN initial margin and extreme loss margin under NSE Clearing's rules, sized to the risk of the underlying moving against the position.
Why does my broker ask for more margin on expiry day?
NSE Clearing levies an additional extreme loss margin of 2% on short index options contracts on the day they expire. For the exact amount on your position, ask your broker, because it collects the margin from you.
Are index options cash-settled while stock options can end in delivery of shares?
Yes. NSE Clearing settles index option exercise in cash. NSE's circular NSE/INSP/47293 says physical settlement is mandatory for all stock derivatives from the October 2019 expiry onwards, so stock futures and options can end in delivery.