Volatility is expected as the monthly derivatives contract expiry comes up on Thursday.
IT, telecom, auto and technology came under selling pressure while oil and gas, realty, capital goods and energy counters witnessed brisk activity.
The 30-share index resumed lower at 26,347.81 and was quoting at 26,387.34 at 1137 hours, loss of 10.37 points, or 0.04 per cent.
The 50-share Nifty too traded flat, down 2.70 points, or 0.03 per cent, at 8,085.90.
Notable gainers were SBI (1.61 per cent), NTPC (1.41 per cent), HUL (1.30 per cent) and GAIL (1.04 per cent).
Meanwhile, foreign fortfolio investors net sold shares worth Rs 629.14 crore last Friday, as per provisional data.
Asian markets piled up more losses from Friday's trading session as investors still struggled to get a sense of the ramifications of the UK's decision to leave the European Union (EU) on finacial markets.
