The Sensex rose for the third straight day in opening trade on the Bombay Stock Exchange (BSE) on Tuesday, adding over 39 points on continued buying by funds and retail investors amid a firming trend in the US market.

The 30-share index of the Bombay Stock Exchange, which has gained over 318 points in the previous two sessions, rose further by 39.29 points, or 0.21 per cent, to 18,568.25 in opening trade.

Stocks of the oil and gas, metals, capital goods and healthcare sectors were trading in the positive zone, which helped the Sensex maintain its rising trend.

In a similar fashion, the broad-based National Stock Exchange Nifty index moved up marginally by 1.80 points, or 0.03 per cent, to 5,552.90.

Brokers said the trading sentiment remained better on the back of a firming trend in the US market, which closed in the positive zone in the previous session, but participants adopted a cautious approach on fears of a possible hike in fuel prices.

Meanwhile, the US Dow Jones Industrial Average ended 0.36 per cent higher on Monday.