Caution prevailed ahead of the beginning of the second part of Parliament's Budget session today as concerns over passage of proposed Bills persisted and focus shifted to key Goods and Services Tax Bill, which is considered as the country's biggest indirect tax reform since Independence.
The Sensex got off to a higher start at 25,891.03 before quoting at 25,653.85 at 1145 hours, a loss of 184.29 points, or 0.71 per cent, from its previous close.
NTPC, Reliance, Tata Steel, BHEL, Axis Bank and Maruti fell between 3.46 per cent and 1.65 per cent.
Foreign portfolio investors (FPIs) bought shares worth a net Rs 191.07 crore last Friday, provisional data from the stock exchanges showed.
Overseas, Asian markets were trading lower as investors awaited central bank meetings in the United States and Japan this week. US stocks had finished mixed during the previous trading last Friday.