Erasing initial gains, the Bombay Stock Exchange Sensex was down by over 80 points at 1030 hours on Friday, on profit-booking.
The Sensex, which had gained 78.88 points in opening trade, fell by 82.63 points to 17,903.25 at 1030 hours after stocks of technology, oil and gas, capital goods and auto companies succumbed to profit-booking.
Similarly, the broad-based National Stock Exchange Nifty index fell by 20.40 points to 5,376.35.
Brokers said profit-booking emerged in late morning trade in the absence of positive cues.
A mixed trend on other Asian bourses also had a negative impact, they said.