The BSE benchmark Sensex gained 91 points to 20,203 in early trade today.The wide-based National Stock Exchange index Nifty moved up by 19 points to 6,133.Brokers said, buying by funds in select stocks amid a better trend in the Asian region mainly influenced the trading sentiment.Japan's Nikkei was up by 0.39 per cent, while trading on the Hong Kong stock exchange had been delayed due to a black rainstorm warning.The US Dow Jones Industrial Average gained 0.34 per cent to close at new all-time highs yesterday.