Shares of the Bombay Stock Exchange (BSE) slipped modestly after the Securities and Exchange Board of India (SEBI) approved a major change in the equity derivatives expiry schedule. Under the new regime effective September 1, 2025, the National Stock Exchange (NSE) will conduct weekly derivatives expiries on Tuesdays, while BSE will shift its expiry day to Thursdays. This marks a reversal from the current structure.