If you trade in Futures &Options (F&O) whether you are an option buyer, seller, or just getting started there are some important changes coming your way. SEBI, the stock market regulator, is rolling out new rules between July and December 2025, and they are going to affect everything from how much margin you will need to which contracts you can trade.
The goal behind these updates is to bring more stability to the F&O space and make it better reflect the actual stock market. Sounds like a lot? Don’t worry we are breaking it all down for you with simple explanations and real world examples, so you’ll know exactly what is changing and how it impacts your trading game.
1. New Eligibility for F&O on Non-Benchmark Indices
What’s Changing? If an index is not a major benchmark (like Nifty 50 or Bank Nifty), it now has to meet stricter requirements to be eligible for F&O trading.
Must have at least 14 stocks in the index No single stock can have more than 20% weightage Top 3 stocks together can’t cross 45% weightage
Effective from: November 3, 2025
Example: If there's a new "Tech India Index" with only 10 stocks and one of them (like TCS) holds 30% weight it won't qualify for F&O trading under the new rules.
2. Position Limits for Single-Stock F&O
What’s Changing? SEBI is capping how many contracts each trader or institution can hold in single-stock futures or options.
For Individual Traders (Retail):
Max: 10% of MWPL (Market-Wide Position Limit)
For FPIs, Mutual Funds, Brokers:
Max: 30% combined
Effective from: October 1, 2025
Option Seller Example: Suppose the MWPL for Reliance is 50 lakh shares. As a retail trader, you can take F&O exposure up to 5 lakh shares (10%). This prevents big bets and reduces manipulation.
3. Expiry Date Changes for Index &Stock Derivatives
What’s Changing?
Starting 28 August 2025, the National Stock Exchange (NSE) is shifting the expiry day for the following derivatives from Thursday to Tuesday:
- NIFTY
- BANKNIFTY
- FINNIFTY
- MIDCPNIFTY
- NIFTYNXT50
- All single-stock derivative contracts
Meanwhile, on the BSE, expiry will continue to remain on Thursday.
Why This Matters: The idea behind this change is to reduce midweek market swings and spread out the F&O action more evenly, so traders have better flexibility and a little more breathing room to manage their positions.
Effective From: 28 August 2025 (NSE)
Example: If you buy a BANKNIFTY weekly call option on the NSE, it will now expire on Tuesday instead of Thursday. This means you’ll need to adjust your strategy and exits earlier in the week.
4. Other Important Changes
Delta-Based Open Interest (OI) Calculation
- OI will now be measured using "Future Equivalent" OI (FutEq OI) — based on delta values, not just contract count.
- This makes it a more realistic reflection of market risk.
Index Options Limits Increased
- Net Limit: ₹1, 500 Cr
- Gross Limit: ₹10, 000 Cr Helps institutions hedge better without overleveraging.
MWPL Now Linked to Cash Volume
- MWPL will now depend on trading volume and free float of the stock.
- High-volume stocks may get higher limits.
Intraday Monitoring of MWPL
- Exchanges will now track F&O usage intraday and can flag excessive exposure instantly.
Pre-Open Session for F&O
- Like in cash markets, a pre-open session is coming to F&O — to reduce volatility and price manipulation.
5. Implementation Timeline - What Happens When?
| Month | What Happens |
| July 2025 | Some rules like expiry changes and OI methodology begin |
| October 1, 2025 | New position limits for single-stock F&O kick in |
| November 3, 2025 | New eligibility rules for non-benchmark indices begin |
| December 2025 | Grace period ends for index position limits – stricter enforcement begins |
Nifty &Index Derivatives - Lot Size Update (2025)
SEBI has also revised lot sizes to align with a minimum contract value of ₹15 lakhs. Here's what you need to know:
| Index | Old Lot Size | New Lot Size (2025) |
| Nifty 50 | 25 | 75 |
| Bank Nifty | 15 | 30 |
| Nifty Midcap Select | 50 | 120 |
| Nifty Financial Services | 25 | 65 |
| Nifty Next 50 | 10 | 25 |
| BSE Sensex | 10 | 20 |
| BSE Bankex | 15 | 30 |
| BSE Sensex 50 | 25 | 60 |
Impact for Option Buyers &Sellers:
For Buyers:
- One contract = higher cost now. Example: Nifty CE trading at ₹100
- Old: ₹100 × 25 = ₹2, 500
- New: ₹100 × 75 = ₹7, 500 More capital needed per trade
For Sellers:
- You’ll need more margin per lot
- But you’ll also receive more premium Example: Selling 1 lot at ₹100
- Premium Received = ₹7, 500 Good for experienced option writers with risk management in place
Final Thoughts
SEBI's latest F&O reforms are focused on:
- Reducing excessive speculation
- Aligning derivatives with real market strength
- Protecting retail investors from wild swings
If you’re a retail trader, don’t be spooked. These changes are about long-term stability. If you're an option seller, margin and lot size increases mean you’ll need more capital but also have more opportunity.
Pro Tip: Keep an eye on expiry dates, stay updated on eligible indices, and manage position sizing smartly especially now with higher lot sizes!
Want personalized F&O strategy help under these new rules? Just ask!