In January 2025, BSE had moved its index options expiry to Tuesday, with NSE concurrently on Thursday. This change, which followed the new regulation on rationalisation of index options, limited each exchange to one index contract expiry per week.
Consequently, BSE’s share in index options had seen a notable increase based on premium turnover, rising from 16% in December 2024 to 23.6% in April 2025.
Goldman Sachs projects that if SEBI allows NSE to shift its expiry to Tuesday, it could impact BSE’s market share.
While both exchanges could have the expiry for their index options contracts on the same day of the week, the brokerage expects Thursdays to be the expiry day for BSE index derivatives.
“The switch in expiry days, if approved by regulators, could reduce BSE’s market share in index options premium by 3-4 percentage points (or -15%) to approximately 18.8% from 22.2% so far this year,” the note elaborated.
This analysis is based on year-to-date trading trends, which show Tuesdays as a particularly active day for options trading, accounting for 24% of India’s options premium – higher than other weekdays (16-19%).