From January 2026, NSE To Trim Lot Sizes In Key Index Derivatives: Here’s What Changes

The National Stock Exchange (NSE) announced a revision in the market lot sizes of major index derivative contracts, with the changes kicking in after the December 2025 expiry cycle. As per the circular, the exchange will reduce the lot sizes for Nifty 50, Nifty Bank, Nifty Financial Services and Nifty Midcap Select, while the lot size for Nifty Next 50 will remain unchanged.

Under the revised structure, the lot size for Nifty 50 will decrease from 75 to 65, Nifty Bank from 35 to 30, Nifty Financial Services from 65 to 60 and Nifty Midcap Select from 140 to 120.

When Do New Lot Sizes Take Effect?

NSE clarified that existing lot sizes will remain applicable to all weekly and monthly contracts up to the December 30, 2025 expiry. Beginning the next

cycle, the revised lots will be visible in the January 2026 weekly and monthly contracts.

For weekly contracts, the final expiry with current lot sizes will occur on December 23, 2025, followed by the first expiry under the revised structure on January 6, 2026. For monthly contracts, the transition happens after the December 30, 2025 expiry, with the January 27, 2026 expiry reflecting the updated lot sizes.

How Will Longer-Duration Contracts Be Transitioned?

The exchange said that quarterly and half-yearly contracts will also shift to the revised lot sizes effective from December 30, 2025 at end of day (EoD). Notably, the March 2026 contract- initially launched as a quarterly expiry- will be treated as a far-month contract starting from the December 2025 monthly expiry.

How Does This Impact Traders?

Adjustments to lot sizes directly impact margin requirements and position sizing for traders and institutions. By reducing lot sizes, NSE aims to improve participation, enhance liquidity and make derivatives trading more accessible without altering the overall contract value significantly.