BSE shares fell as much as 4.5% to Rs 3,292.30 on Monday, extending their decline for a fourth consecutive trading session after Jefferies downgraded the stock to Underperform from Hold and cut its price target to Rs 2,940 from Rs 3,520.

The stock has fallen 8% over the past four trading sessions. Trading volume was more than four times its 20-day average, according to Bloomberg data.

Jefferies’ downgrade reflects concerns over risks to BSE’s revenue from domestic proprietary traders, which the brokerage estimates accounts for about 50% of notional turnover. The brokerage also cited the higher securities transaction…