How Much Margin Do You Need for One Sensex Futures Lot?
You need roughly 1 to 1.4 lakh rupees in margin for one lot of Sensex futures. The exact amount depends on the live Sensex level and SPAN margin set by the exchange that day.
Most retail traders think they need 50,000 to 70,000 rupees to trade one lot of Sensex futures. The actual number is closer to 1.1 to 1.4 lakh rupees per lot in normal market conditions. The exact amount changes daily because it is calculated as a percentage of contract value, and Sensex moves all the time. To follow the math you only need a basic grip on what is NIFTY and Sensex futures and how the exchange charges margin.
The quick answer in numbers
Sensex futures use a lot size of 10. So one lot represents 10 times the Sensex value. The initial margin is the sum of two pieces fixed by SEBI rules.
- SPAN margin: Around 6% to 9% of contract value, varies with index volatility.
- Exposure margin: Around 3% to 5% of contract value.
Total: roughly 10% to 14% of the lot value. With Sensex around 78,000, one lot is worth 7.8 lakh rupees. Total initial margin is therefore in the 78,000 to 1.1 lakh band on calm days, and up to 1.4 lakh on volatile ones.
Sensex futures contract specs you need to know
| Specification | Value |
|---|---|
| Underlying index | BSE Sensex (30 stocks) |
| Lot size | 10 |
| Tick size | 0.05 points |
| Tick value | 0.50 rupees per tick per lot |
| Expiry | Last Friday of every month (also weekly) |
| Settlement | Cash settled in rupees |
BSE switched the Sensex futures lot from 15 to 10 in mid-2024 to bring it closer to NIFTY futures lot size. The change made the product more accessible to small traders.
The math, line by line
Take Sensex at 78,000 as an example.
- Lot size = 10
- Contract value = 78,000 × 10 = 7,80,000 rupees
- SPAN margin (assume 8%) = 62,400 rupees
- Exposure margin (assume 4%) = 31,200 rupees
- Total initial margin = 93,600 rupees
That is the figure your broker will block in your trading account before letting you place the order. The same trade on a high-volatility day with SPAN at 11% and exposure at 5% would block 1,24,800 rupees instead. The exchange updates margin parameters every evening based on observed volatility.
What changes the margin from day to day
Three things move the number.
- Sensex level itself. A 5% rally pushes contract value up 5%, and margin scales with it.
- Volatility regime. Around big events — Budget, RBI policy, US Fed meeting — SPAN margin rises sharply.
- Calendar position. Margin requirement creeps up in the last week before expiry to discourage last-minute speculation.
A trade you placed comfortably with 95,000 rupees on Monday could need 1.2 lakh by Thursday if the market gets choppy.
Margin you need vs cash you should keep
The exchange asks for the initial margin to open the trade. That is not the same as the cash you should hold. Smart Sensex futures traders keep an extra cushion for three reasons.
- Mark-to-market losses. Daily losses are debited from your account. Without buffer cash, your broker will square off the position.
- Margin top-up calls. If volatility expands, the exchange asks for more SPAN. You need free cash to top up.
- Pin risk near expiry. Last-day moves can be sharp. Extra cash keeps you in the trade rather than getting stopped out at a bad price.
A practical rule: hold at least 1.5 times the initial margin in your account. So for a 1 lakh margin trade, keep 1.5 lakh in cash plus pledged collateral.
How Sensex futures margin compares with NIFTY futures
| Item | Sensex futures | NIFTY futures |
|---|---|---|
| Lot size | 10 | 75 |
| Index level (illustrative) | 78,000 | 22,000 |
| Contract value | 7.80 lakh | 16.50 lakh |
| Approx initial margin | 95,000 | 2.0 lakh |
| Best for | Small accounts, Sensex traders | Larger accounts, NIFTY traders |
Sensex futures are now the cheaper way to trade Indian large-cap index futures, simply because the lot is smaller. That is why volume has grown rapidly on BSE since the lot change.
Where to check the live margin number
Use your broker's margin calculator on their website or app. They pull live SPAN and exposure data from the exchange end-of-day file. You can also see the official notifications on the BSE website for any margin parameter change.
How to lower your margin needs without losing the trade
If 1 lakh per lot feels heavy, three options can stretch your capital without leaving the futures segment.
- Use spreads. A calendar spread (long near month, short far month) attracts a far smaller margin than a single naked future.
- Use options as a synthetic. A long call plus short put at the same strike behaves like a long future but lets you size in much smaller pieces.
- Pledge mutual funds. Liquid debt funds attract a small haircut and free up most of your idle savings as usable margin.
Each route has trade-offs. Spreads cap your profit. Synthetic positions add option-specific risks. Pledging needs you to keep 50% in cash. Pick the one that matches your risk tolerance, not just the lowest margin number.
FAQ
Can I trade Sensex futures with intraday margin only?
Yes. Most brokers allow intraday positions with around 30% to 40% of the full overnight margin. The catch is the auto-square-off well before close, usually 15 to 30 minutes early.
Is the margin the same for buy and sell?
Yes. Long and short futures trades attract the same SPAN plus exposure margin.
Does pledging shares reduce the cash margin needed?
Yes. You can pledge approved shares or mutual funds and use them as collateral for SPAN. You still need at least 50% in cash to cover daily losses.
What happens if I run out of margin mid-trade?
The broker sends a margin call. If you do not add funds quickly, they square off the position at market price, sometimes at a loss.
Frequently Asked Questions
- Can I trade Sensex futures with intraday margin only?
- Yes. Most brokers offer 30% to 40% of the overnight margin for intraday positions, with mandatory auto-square-off 15 to 30 minutes before market close.
- Is the margin the same for buy and sell?
- Yes. Long and short futures trades attract the same SPAN plus exposure margin requirement.
- Does pledging shares reduce the cash margin needed?
- Yes. You can pledge approved shares or mutual funds and use them as collateral for SPAN. You still need at least 50% in cash to cover daily losses.
- What happens if I run out of margin mid-trade?
- The broker sends a margin call. If you do not add funds quickly, the position is squared off at market price, often at a loss.