SEBI has approved NSE's shift of weekly F&O expiry to Tuesday from June 15, aligning it with MSE, while BSE retains Tuesday expiry. Exchanges must now pick either Tuesday or Thursday for all derivative contracts. The move aims to reduce volatility and speculative activity. Existing contracts will retain their expiry day, while contracts expiring post-Sept 1, 2025, will shift to Thursday. No new weekly index futures will be introduced after July 1, 2025. Monthly contracts will now expire on the last Thursday from September onward.