BSE Ltd.’s shares have been placed under extra scrutiny to caution investors and deter any speculative trading, following a sharp rally in the bourse’s stock price.

With the inclusion in the so-called additional surveillance measure, trading in BSE shares — listed on its privately held larger rival National Stock Exchange of India Ltd. — will attract 100% margin. Stocks are shortlisted for ASM based on factors such as sharp price movement, high volumes, and concentrated client activity.

BSE’s shares fell more than 3% on Wednesday, the most in about three weeks.