Reminder for F&O traders: Lot sizes of Nifty, Bank Nifty, two other NSE indices change from tomorrow

Reminder for F&O traders: Lot sizes of Nifty, Bank Nifty, two other indices change from tomorrow

With December 30 being the monthly F&O (futures & options) expiry of various NSE indices, traders should be mindful of change in lot sizes of contracts from December 31.

In October, the National Stock Exchange (NSE) had announced a revision in the market lot sizes of several major index derivative contracts, with the changes scheduled to take effect after the December 2025 expiry cycle. As per the circular, the lot sizes for Nifty 50, Nifty Bank, Nifty Financial Services, and Nifty Midcap Select will be reduced. The Nifty 50 lot size will be revised 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. NSE also clarified that the lot size for Nifty Next 50 will remain unchanged.

The exchange stated that existing lot sizes will continue to apply to all weekly and monthly contracts until the December 30, 2025 expiry. From the next cycle, the January 2026 weekly and monthly contracts will reflect the revised market lots. For weekly contracts, the last expiry with the current lot sizes will be on December 23, 2025, followed by the first expiry with the revised lot size on January 6, 2026. Similarly, the monthly contracts will shift to the revised structure after the December 30, 2025 expiry, with the January 27, 2026 expiry carrying the updated lot sizes.

NSE also added that quarterly and half-yearly contracts will transition to the new lot sizes effective from December 30, 2025, at EoD. The March 2026 contract, initially introduced as a quarterly expiry, will now be treated as a far-month contract from the December 2025 monthly expiry onward.

Traders will need to adjust position sizes and margin requirements, while retail investors may find contracts more accessible as they will need lesser capital.

The NSE revises lot sizes of Futures & Options contracts primarily to keep the contract value within a standard range, to keep the contracts affordable and standardized. Since derivatives are leveraged instruments, traders do not have to pay the full value of the contract upfront, but the lot size determines their exposure and the margin required. The NSE undertakes lot size revisions to ensure market efficiency and liquidity, and to contracts more acceptable for a broader set of market participants.