Divya Delhi :In Monday's trade, BSE Ltd. shares fell more than 17%, their biggest intraday decline on record, after Sebi ordered the exchange to pay regulatory fees based on the notional value of its options contracts, not the premium value.Sebi wrote on Friday that BSE must pay regulatory fees and 15% interest depending on annual revenue and the "notional value" of its options contracts.Premium turnover is the total premium paid on all derivatives contracts, whereas notional turnover is the entire strike price. Using notional turnover as the base raises regulatory fees.According to Jefferies India, since derivatives account for 40% of BSE's FY25 and FY26 anticipated net profits, additional fees might reduce earnings per share by 15-18%.Jefferies lowered the stock to hold from buy.BSE shares dropped to ₹2,612 early in the day, but recovered to trade at ₹2,792, down over 13% on the National Stock Exchange. The trade volume was 10.11 million shares.Following a directive from the Securities and Exchange Board of India (Sebi), the market regulator, the stock exchange of Bombay Stock Exchange (BSE) Ltd. to pay regulatory fees based on the notional value of its options contracts rather than the premium value,