NSE Implements New Lot Sizes for Nifty, Bank Nifty and Other Index Derivatives

The National Stock Exchange implements revised market lot sizes for major index derivatives. The changes, which were announced back in October through circular NSE/FAOP/70616, are now taking effect for quarterly and half-yearly contracts.

What's Changing Today?

As of end of day today, December 30, 2025, lot sizes for four major index derivatives have been revised:

Nifty Next 50 (NIFTYNXT50) remains unchanged at 25 units per lot.

Understanding Today's Implementation

Today is the last expiry for monthly contracts with the old lot sizes for NIFTY, BANKNIFTY, FINNIFTY, and MIDCPNIFTY. From January 27, 2026, onwards, all monthly contracts will use the new reduced lot sizes.

More importantly, all existing quarterly and half-yearly contracts will have their lot sizes revised from today (EOD). This means if you're holding positions in quarterly or half-yearly contracts, your contract specifications are changing today.

What This Means for Your Positions

For traders holding quarterly and half-yearly positions, here's what's happening:

• NIFTY Quarterly & Half-Yearly Contracts: All existing quarterly and half-yearly contracts expiring on March 31, 2026, will shift to the new lot size of 65 (down from 75) after today's close.
• BANKNIFTY Quarterly Contracts: All existing quarterly contracts expiring on March 31, 2026, will shift to the new lot size of 30 (down from 35) after today's close.

The March 2026 contract, which was introduced as a quarterly contract, will now become a far month contract from today.

Timeline for Different Contract Types

The implementation has been phased differently based on contract type:

Weekly Contracts (NIFTY only):

• Last expiry with old lot size: December 23, 2025 (already passed)
• First expiry with new lot size: January 6, 2026

Monthly Contracts:

• Last expiry with old lot size: Today, December 30, 2025
• First expiry with new lot size: January 27, 2026

Quarterly & Half-Yearly Contracts:

• Lot size revision: Today, December 30, 2025 (EOD)
• Next expiry: March 31, 2026*

*The March 2026 contract transitions to far month contract status from today.

Why These Changes Were Made

These revisions follow SEBI's guidelines from circular SEBI/HO/MRD-PoD2/CIR/P/2024/00181 dated December 30, 2024. The regulatory mandate requires periodic reviews to keep contract values within reasonable limits as index levels fluctuate. NSE calculated the revised lot sizes based on average closing prices from September 2025.

You can review the complete NSE circular here.

Important Notes for Today

Since today is the transition date, traders should be aware that:

• Traders can open fresh positions with the new lot size from tomorrow onwards.
• Trading members should have already updated their systems with the latest contract files from NSE's Extranet server.
• Any positions in quarterly and half-yearly contracts will reflect the new lot sizes from tomorrow onwards.

Complete Implementation Schedule

Here's the full schedule as outlined in the NSE annexure

For NIFTY, BANKNIFTY, FINNIFTY, and MIDCPNIFTY:

For Quarterly and Half-Yearly Contracts: