The National Stock Exchange (NSE) will implement revised lot sizes for Nifty, Bank Nifty, Nifty Financial Services, and Nifty Midcap Select index futures and options contracts starting with the January 2026 series. These changes aim to align notional values with current index levels and improve market efficiency. The adjustments will affect weekly, monthly, quarterly, and half-yearly contracts from their respective January 2026 expiries. Contracts expiring in December 2025 will continue under existing lot sizes.