Shares of the Bombay Stock Exchange Ltd. (BSE) fell as much as 9% on Monday after the National Stock Exchange made changes to the day of the expiry of its weekly and monthly contracts.

NSE announced on Monday evening the Nifty weekly contracts, which currently expire on Thursday, will now expire on Monday every week.

The Monthly, Quarterly and Half Yearly contracts, the Nifty Bank monthly and quarterly contracts, and the Financial Services, Nifty Midcap and Nifty Next 50 Monthly Contracts, which expire on the last Thursday of every month, will now expire on the last Monday helps.

The circular will come into effect on April 4. BSE currently has its expiry on Tuesday.
NSE has made these changes to possibly regain some lost market share against BSE. It is possible that BSE has a higher market share on Friday and Monday and hence NSE intends to recapture the same.

There is also a probability that there will be greater action on Friday, since participants may not want to come and carry positions in to the weekend and square them off.

In an interaction with CNBC-TV18, NSE’s Chief Business Development Officer Sriram Krishnan said that it makes sense to keep an optimal day to expire the Nifty Contract.

Krishnan added that there are plenty of geopolitical developments taking place over the weekend and hence Monday will be a great day to have the expiry. He added that NSE has received a lot of feedback post this news but the change has been announced keeping the efficiency and seamlessness in mind.

Shares of BSE are currently trading 8% lower at ₹4,090. The stock is down 33% from its recent peak of ₹6,133.

(To be updated with more.)