Index derivative lot sizes

How lot sizes work

A derivative contract is not quoted per unit of the index — it is quoted per lot. The lot size is how many units of the underlying one contract carries, and orders are placed in whole lots. One NIFTY contract at a lot size of 65 therefore moves 65 times whatever the index moves.

Contract value is what actually drives the number

Contract value = index level × lot size. SEBI requires an index derivative contract to be worth roughly ₹15–20 lakh, so as an index drifts up or down the lot size has to be re-set to pull contract value back into that band. That is why lot sizes fall when an index has risen: with NIFTY near 25,000, a lot of 65 is worth about ₹16.25 lakh, whereas the old lot of 75 would have been about ₹18.75 lakh.

Why they change on a schedule, not on a whim

The revisions are periodic and formula-driven. NSE's October 2025 circular states that it used the average closing level of each underlying index over a one-month period (September 2025) to compute the revised lots. BSE's October 2024 notice used the average close from 16 September to 15 October 2024. The exchange publishes the result in advance, which is exactly why this page stores two dates per row.

Edge cases that catch people out

A revision announced is not a revision applied

NSE/FAOP/70616 is dated 3 October 2025 and came into effect from 28 October 2025 end-of-day — but weekly and monthly contracts that already existed kept the old lot right through to the 30 December 2025 expiry. For nearly three months, two different lot sizes were simultaneously correct depending on which contract you held. A page that swaps in the new number on the day the circular appears is wrong for that whole window, and a page that waits until the change is everywhere is wrong for it too.

Long-dated contracts are revised in place

Quarterly and half-yearly contracts are not left to run out at the old lot. NSE revised the lot size of existing quarterly and half-yearly contracts at 30 December 2025 end-of-day; BSE did the equivalent for long-dated SENSEX contracts at 27 December 2024 end-of-day.

Each exchange runs its own clock

SENSEX is a BSE contract, so its lot was set by a BSE notice a full year before the NSE revision, with its own run-off dates for monthly, weekly and long-dated contracts. Reading one exchange's circular tells you nothing about the other's.

Quantity freeze is a separate limit

The lot size is not the largest order you can place. Each exchange also publishes a quantity freeze — the maximum quantity accepted in a single order for that contract. Anything larger has to be broken into several orders. The freeze quantity is published and revised by the exchange independently of the lot size, so look up the current figure rather than assuming it.

Single-stock contracts are on a different cycle

This table covers index derivatives only. Lots for individual stock futures and options run to roughly two hundred symbols and are revised on their own schedule; publishing them without reading each circular is the mistake this page exists to avoid.

Effective-date notes, straight from the circulars

If you are studying for NISM Series VIII

The NISM-Series-VIII Equity Derivatives Certification Examination workbook deals with lot size under contract specifications — the set of terms that define a contract: the underlying, the market lot, the tick size, the expiry day and the settlement mechanism. The workbook explains why a market lot exists (a standardised contract is what makes an exchange-traded derivative fungible, and the minimum contract value is a regulatory input to it) and how contract value follows from it.

What a workbook cannot do is stay current. Any specific lot size printed in study material is a snapshot of the circular in force when that edition was written. For the exam, learn the mechanism; for anything real, read the number off the current exchange circular — the reference column above links to it.