Why SEBI revises F&O lot sizes: the contract-value band and the resize timeline
The short answer
SEBI does not set the lot size directly. It fixes a target contract value for index derivatives, and the lot is derived so that lot size times the index price lands inside that band. Since October 2024 the minimum has been about ₹15 lakh at introduction, reviewed to stay within roughly a ₹15 lakh to ₹20 lakh band. As an index rises over the years, the lot is cut in steps to keep the contract value in range, so a lot revision is the visible output of a policy about notional size, not a change of heart about risk.
Traders tend to read a lot-size change as a piece of news that happened to them: the number moved, margins moved, everything feels different for a week. Read correctly it is the opposite of news. It is a deterministic consequence of one policy variable, the contract value, colliding with one market variable, the index level. Fix the first and let the second drift, and periodic lot revisions are guaranteed. This guide is the why. It explains the band mechanism that generates every revision, the rationale SEBI built it for, and the 2024 to 2026 chronology that shows the machine running. For what a lot is as a unit, see the companion guide on what a lot size in F&O is; for the step-by-step mechanics of how a revision is executed by the exchange, see the related article on how and when contract sizes change.
The core mechanism: the contract-value band
Start from the identity that governs everything downstream. For an index derivative, the notional contract value of one lot is simply the number of index units in the lot multiplied by the level of the index:
contract value = lot size × index price
SEBI regulates the left side of that equation, not the lot. It mandates that a new contract must be worth at least a floor amount when it is introduced, and that on each periodic review the value must sit inside a band. The lot size is whatever integer makes that true at the prevailing index level. Rearranged, the lot the exchange must publish is the target value divided by the price, rounded to something tidy:
lot size ≈ target contract value ÷ index price
That single rearrangement is the whole engine. It tells you three things at once. First, the lot is an output, never an input: nobody at SEBI or the exchange picks 75 or 65 because it is a nice number, they pick the band and the arithmetic returns the lot. Second, the lot moves inversely to the index: a higher index at review means a smaller lot to hold the product of the two inside the band. Third, whenever SEBI lifts the band, every lot is cut in a single step to lift the notional up to the new floor. The rest of this guide is those three consequences playing out.
Why a rising index forces the lot down
Hold the lot constant and let the index appreciate, and the contract value climbs with it. A lot of 75 index units at a level of 20,000 is a ₹15 lakh contract; at 24,000 the very same lot is worth ₹18 lakh, and at 27,000 it is over ₹20 lakh and out the top of the band. The exchange cannot let the notional wander, so at the next review it cuts the lot to pull the value back inside. Over a multi-year bull phase this produces a distinctive shape: the index staircases up, and the lot staircases down to meet it, each downward step a discrete revision timed to a review.
This is the single most misread fact about lot revisions. A cut in the lot looks, on the surface, like the regulator loosening its grip, letting people in with a smaller position. It is usually the reverse of a signal about risk. The lot fell because the index rose, and the contract value, the thing SEBI actually controls, is being held right where it was. The exposure per lot has not shrunk in the way it feels like it has; it has been kept deliberately large. Reading the staircase correctly is the difference between thinking the rules relaxed and understanding that nothing about the policy changed at all.
The rationale: suitability, priced in rupees
Why hold the notional high on purpose? Because the minimum contract value is a suitability filter expressed in money. A large minimum notional means the smallest position a retail participant can take in an index derivative is a serious commitment of capital and margin, not a lottery ticket bought on a whim. SEBI framed the October 2024 recalibration in exactly those terms: given the inherent leverage and higher risk in derivatives, lifting the minimum contract size in step with the market growth was meant to keep an in-built suitability and appropriateness criterion for participants. The band is the instrument; suitability is the intent.
The backdrop is the regulator's own loss data, and it is stark enough that no invented figures are needed. In its September 2024 study covering the three years from FY22 to FY24, SEBI found that 93 percent of individual traders in equity derivatives made a net loss, with aggregate losses exceeding ₹1.8 lakh crore and only about 1 percent of traders clearing more than ₹1 lakh in profit after costs. Its follow-up FY25 study, published in July 2025, found that 91 percent of individual equity-derivatives traders still lost money, and that their aggregate net loss widened to about ₹1,05,603 crore in that single year. A framework that raises the price of entry is one lever against that backdrop.
The resize timeline, 2024 to 2026
The chronology is where the mechanism stops being abstract. Three moments matter: the framework that set the new band in October 2024, the upward resize that took effect in November 2024 to meet it, and the downward review effective from the January 2026 series as the indices climbed through 2025. Presented as a sequence, it is simply the band engine running forward in time.
| When | What changed | Why (the band logic) |
|---|---|---|
| Before Oct 2024 | Minimum contract value about ₹5 lakh to ₹10 lakh | The older, lower notional floor that the recalibration replaced |
| 1 Oct 2024 | SEBI framework: minimum contract value not less than ₹15 lakh at introduction, reviewed within a ₹15 lakh to ₹20 lakh band | Suitability lever: lift the minimum notional in step with market growth to keep derivatives a serious commitment |
| 20 Nov 2024 | New index-derivative contracts resized UP to meet the ₹15 lakh floor; existing weekly and monthly contracts ran to expiry, longer-dated ones transitioned near end-December 2024 | Lots had to rise in a single step to lift the notional up to the new, higher band |
| Through 2025 | Indices appreciated; the contract value of an unchanged lot drifted upward | Rising index price pushes lot × price toward the top of the band |
| Jan 2026 series | Several index-derivative lots revised DOWN (for example the widely-followed large-cap and banking-sector index lots), set from a reference-month average in late 2025 | Lots cut to pull the contract value back inside the band after the 2025 rise |
Timeline compiled from SEBI and exchange circulars. The exact lot numbers for any contract are a moving target reviewed periodically; treat every figure here as a dated snapshot and confirm against the current exchange list before relying on it.
Current lots: the band logic, not a number to memorise
It is tempting to end with a clean table of "the current lot sizes," but that table is stale the moment an index moves enough to trigger the next review. The honest and more useful thing is to give you the band logic and a worked illustration, then point you to the authoritative list. Below is how the arithmetic lands at a few index levels, so you can reconstruct a plausible lot yourself and, more importantly, sanity-check any figure you read elsewhere against the band.
| Index level (illustrative) | Target contract value | Implied lot (value ÷ price, rounded) | Lot × price (check) |
|---|---|---|---|
| 15,000 | ₹15,00,000 | ≈ 100 | ₹15,00,000 |
| 20,000 | ₹15,00,000 | ≈ 75 | ₹15,00,000 |
| 24,000 | ₹15,00,000 | ≈ 62 to 65 | ₹14.9 lakh to ₹15.6 lakh |
| 50,000 (a higher-priced index) | ₹15,00,000 | ≈ 30 | ₹15,00,000 |
The pattern is exactly the inverse relationship the band guarantees: the higher the index, the smaller the lot for the same target value. Real exchange lots differ from these round illustrations because the exchange averages the index over a reference window and rounds to a convenient integer, and because a contract can sit anywhere inside the band rather than exactly on the floor. But if a figure you read implies a contract value far outside a ₹15 lakh to ₹20 lakh band at today's index level, that is your signal the figure is out of date. Verify the current lot against the latest exchange circular; do not memorise a number.
The effect: larger notional, higher margin, a raised floor
Everything the band does converges on one downstream fact: a single lot is a large position by design, and periodic cuts do not undo that. Because the notional per lot is held near ₹15 lakh or above, the leverage embedded in a derivative acts on a large base, and the margin the exchange demands to hold one lot scales with that notional. That is what actually reaches the retail account: the amount of capital a single position ties up, and the amount at risk if it moves against you, are both anchored to a deliberately high floor.
This is where the framework meets the lot-size-floor problem that faces the smallest accounts. When one lot is a ₹15 lakh-plus commitment, the account size at which taking that lot is a sensible fraction of capital rises with it, and accounts below that level are effectively priced out of the index-derivative segment. That is not a side effect; it is the mechanism working as intended, sorting participants by the size of commitment they can prudently make. The detailed arithmetic of how the lot floor collides with sound position sizing is worked through in the guide on position sizing for Indian retail, and the index-specific case appears in the primer on the banking-sector index.
| Scenario (illustrative) | Lot | Index level | Contract value | Rough margin at about 15% |
|---|---|---|---|---|
| Pre-2024 floor | 50 | 20,000 | ₹10,00,000 | ≈ ₹1.5 lakh |
| Post Nov 2024, band lifted | 75 | 20,000 | ₹15,00,000 | ≈ ₹2.25 lakh |
| 2025, index rises, lot unchanged | 75 | 24,000 | ₹18,00,000 | ≈ ₹2.7 lakh |
| Jan 2026, lot cut back into band | 65 | 24,000 | ₹15,60,000 | ≈ ₹2.34 lakh |
The margin percentage here is a round illustration, not a quoted rate; actual span-plus-exposure margin is set by the clearing corporation and varies by contract and volatility. What the illustration shows is the shape: the 2024 reset stepped the notional and margin up, the 2025 rise carried them higher still, and the 2026 cut trimmed them back toward the band without returning to the pre-2024 world. The floor moved up and stayed up. Judging whether a given lot is a prudent size for a given account, rather than reacting to the headline number, is upstream work, and that judgement is exactly what the method we teach is built around.
How to read the next revision without surprise
Because the whole system is deterministic, you can anticipate revisions instead of being caught by them. Watch the contract value, not the lot. Take any lot's current notional as index level times lot size; if a sustained move has carried that product toward the top of the band, a downward lot revision at the next review is the likely resolution, and if SEBI signals a higher band, expect an upward step across the board regardless of where the index sits. When a circular does land, the two questions that resolve it are always the same: is this a periodic review driven by the index level, or an ad-hoc change driven by a new band, and what is the transition schedule for existing versus new contracts. The step-by-step reading of a revision circular is covered in the companion piece on how and when contract sizes change; this guide has given you the reason any of it happens.
Where this sits in the curriculum
Contract specifications and the lot as a unit are foundational, introduced early in Stage 1. The regulatory rationale and the band mechanism belong to the market-structure and risk material in Stage 2, where the reasoning behind a rule matters more than the current value of any figure, because figures date and reasoning does not. The position-sizing consequences, translating a ₹15 lakh-plus lot into a defensible fraction of a real account, are worked in the Stage 1 sizing volume and revisited whenever the framework moves. The through-line is the same one this guide argues: understand the machine that generates the numbers, and no single revision can blindside you.
Frequently asked questions
Why does SEBI revise F&O lot sizes at all?
+SEBI does not target the lot size directly. It sets a minimum and target contract value for index derivatives so that one lot represents a deliberately large notional exposure. The lot size is then derived from that value and the current index level. Because the index level drifts over time, the lot has to be revised periodically to keep the contract value inside the mandated band. The purpose is suitability: a larger minimum notional is intended to keep the smallest, least-prepared accounts out of leveraged derivatives.
What is the contract-value band for index derivatives?
+Under the framework SEBI announced on 1 October 2024, a new index-derivative contract must have a value of not less than ₹15 lakh at the time it is introduced, and the lot size is fixed so that on the day of review the contract value sits within a band of roughly ₹15 lakh to ₹20 lakh. This replaced the earlier ₹5 lakh to ₹10 lakh minimum. The band, not the lot number, is the fixed policy variable. Verify the current band, as SEBI reviews it.
How is the lot size actually calculated from the band?
+In principle the lot is the target contract value divided by the index price, rounded to a convenient whole number. If the target is about ₹15 lakh and the index trades near 20,000, the lot is roughly 15,00,000 divided by 20,000, which is about 75. Exchanges use an average of the index over a reference period rather than a single day's close, and round to a tidy figure, but the arithmetic is that simple: lot size is approximately target contract value divided by index price.
Why does a rising index force the lot size down?
+Contract value equals lot size times index price. If the lot is held fixed while the index rises, the contract value drifts up and out of the band. To pull it back inside, the exchange cuts the lot. So a sustained rise in the index level produces a staircase of downward lot revisions over the years, each one a step that keeps lot times price inside the mandated range. A downward lot revision is therefore usually a sign the index has risen, not that risk has fallen.
What changed in November 2024?
+From 20 November 2024, new index-derivative contracts had to meet the higher minimum contract value of about ₹15 lakh, up from the previous ₹5 lakh to ₹10 lakh. Exchanges revised lot sizes upward in a single step to lift the notional into the new band. Existing weekly and monthly contracts ran to expiry on their old lots, while longer-dated contracts transitioned near the end of December 2024. It was the largest single jump in the minimum contract value in years.
Were lot sizes cut again in early 2026?
+Yes. Because the indices rose through 2025, the exchange revised several index-derivative lot sizes downward for the contract series that took effect in January 2026, reducing the widely-followed large-cap index lot and the banking-sector index lot, among others. The new lots were set from an average of the index over a reference month in late 2025 so that the contract value stayed inside the mandated band. Verify the exact current lots before you rely on any number, as they change.
Does a lot cut make derivatives cheaper or safer?
+A downward lot revision lowers the rupee notional and the margin of a single lot at that moment, which can look like relief. It does not lower risk in any structural sense, and it does not undo the higher band. Since 2024 the whole point of the framework has been to hold the minimum notional high. A single lot still represents a large exposure by design, and the leverage in derivatives still magnifies both gains and losses. The band is the policy; the lot number just tracks it.
How does the resized lot affect a small account?
+The larger minimum contract value raises the notional and the margin required to hold one lot, so the account size at which a single position is a sensible fraction of capital has risen too. An account that could take one index-derivative lot before the 2024 reset may find one lot is now too large a bet relative to its capital. That is the intended effect: the framework is part of SEBI's retail-derivatives risk agenda, priced in rupees rather than stated as a ban.
Where can I find the current, verified lot sizes?
+The exchange publishes the authoritative list of market lot sizes for every derivative and issues a circular whenever it revises them. Because lots are reviewed periodically and change with the index level, any figure in an article, including this one, should be treated as a snapshot and checked against the latest exchange circular before use. Rely on the band logic to understand why a number is what it is, and on the exchange list for the number itself.
Sources
Where the facts come from
- SEBI index-derivatives framework, 1 October 2024. The measure raising the minimum contract value for index derivatives to not less than ₹15 lakh at introduction, with the lot fixed so the contract value on review sits within a ₹15 lakh to ₹20 lakh band, up from the earlier ₹5 lakh to ₹10 lakh; effective for new contracts from 20 November 2024. sebi.gov.in
- Exchange lot-size revision circulars. The upward resize of index-derivative lots effective 20 November 2024 to meet the new band, and the downward revision effective from the January 2026 contract series (lots set from a reference-month average in late 2025). The exchange publishes the authoritative current market-lot list and each revision circular.
- SEBI study, individual traders in equity derivatives, FY22 to FY24. Published September 2024: 93 percent of individual traders made a net loss, aggregate losses over ₹1.8 lakh crore, about 1 percent clearing more than ₹1 lakh in profit. sebi.gov.in
- SEBI study, FY25. Published July 2025: 91 percent of individual equity-derivatives traders lost money, with aggregate net losses widening to about ₹1,05,603 crore in the year. Reported alongside the phased index-derivatives measures.
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Take the free diagnostic →Related reading
- What is a lot size in F&O? The companion primer: what the lot is as a unit, and how contract value drives notional and margin.
- SEBI lot-size revisions explained: how and when contract sizes change. The step-by-step mechanics of a revision and how to read the circular.
- Position sizing for Indian retail traders. The arithmetic of fitting a large-notional lot to a real account.
- What is the banking-sector index? The index behind one of the most-traded derivative lots.
- What is leverage in trading? Why a large notional per lot matters so much.