NSE Revises Lot Sizes for Nifty, Bank Nifty Derivatives: New Contract Specifications Effective from December 30

The National Stock Exchange of India (NSE) has announced a revision in the market lot size for derivative contracts across four key indices, including the flagship Nifty 50 and Nifty Bank. The changes, mandated by the Securities and Exchange Board of India (SEBI) guidelines for periodic lot size review, aim to adjust the notional contract value and will come into effect from October 28, 2025 (End of Day).

The revision was calculated based on the average closing price of the underlying indices during the one-month period of September 2025.

Key Lot Size Changes

Implementation Timeline for Contracts

The new lot sizes will be implemented in a phased manner, depending on the contract's expiry cycle:

• Weekly and Monthly Contracts: The existing lot sizes will remain applicable for all weekly and monthly contracts expiring up to December 30, 2025.

• The first Nifty Weekly contract to trade with the revised lot size of 65 will be the one expiring on January 06, 2026.
• The first Monthly contracts for Nifty, Nifty Bank, Nifty Financial Services, and Nifty Mid Select to trade with the revised lot sizes will be those expiring on January 27, 2026.
• Quarterly and Half-Yearly Contracts: The lot size of all existing quarterly and half-yearly contracts will be revised automatically at the end of the day on December 30, 2025.

The NSE has advised its members to inform clients who hold existing positions or plan to initiate new positions in the quarterly and half-yearly contracts about the upcoming revision.

Temporary Order Book Restrictions

The circular also noted that the day spread order book will be disabled for the following contract combinations during the transition period:

• November 2025 – January 2026
• December 2025 – January 2026
• December 2025 – February 2026

Trading members are also required to update their systems with the latest contract files provided by the exchange on the extranet server before the respective effective date.

How Does Lot Change Affect Traders & Investors?

The Nifty futures contract that previously represented 75 units of the index will now represent 65 units starting December 30, 2025. The following are the effects that investors & traders have to consider while trading in the markets:

• The change affects the margin required for a single lot since the contract value depends on both lot size and the index price.
• Traders managing large positions or using hedging strategies may need to recalculate position sizes and update margin requirements, as a smaller lot reduces the notional value per contract.
• Overall, this revision could influence trading strategies, risk management decisions, and market participation for both institutional and retail investors.