India’s stock exchanges will see a significant shift in their derivatives trading calendars, following a directive from the Securities and Exchange Board of India (Sebi) that aims to streamline weekly options expiries and reduce market volatility.

Starting September 1, 2025, the National Stock Exchange (NSE) will move its weekly F&O expiry to Tuesdays, while the BSE will standardise its expiry on Thursdays—a reversal of their earlier schedules.

The move follows Sebi’s decision to restrict exchanges to offering expiries on only one fixed day per week—either Tuesday or Thursday—for index derivatives, a measure designed to prevent overcrowding of expiry dates, limit excessive speculative trading, and provide clearer, more stable trading windows.

The change also marks a new chapter in the rivalry between the two exchanges. Over the last year, BSE has rapidly grown its derivatives market share on the back of innovation and pricing strategies, even attracting volume away from the NSE. In March, BSE’s stock surged nearly 18% after Sebi proposed the expiry limitation, signalling investor optimism that the older exchange could benefit from a more level playing field. NSE, meanwhile, shelved its earlier plan to shift to Monday expiries, settling instead on Tuesday to comply with the new rule. The chosen days now give each exchange breathing room in the trading week.

Existing contracts will continue their legacy expiry schedules until the end of August, but from September 1, all new weekly index options will align with the new expiry days.

Monthly index F&O contracts will expire on the last Thursday of each month for the BSE, while the same cadence applies for the NSE, except the shift to Tuesday for weeklies. By enforcing this structured separation, the regulator is looking to decongest expiry-day volatility that has become a hallmark of recent options-driven trades. The regulator has also introduced other reforms to curb speculative bursts—such as increasing margins on expiry days and limiting exchanges to one weekly contract per index.

With options trading now accounting for the lion’s share of daily turnover, Sebi appears increasingly concerned about systemic risks emerging from derivatives liquidity clustering on certain days.