The Bombay Stock Exchange benchmark Sensex is trading in green in the afternoon trade. The Sensex was trading at 17442, up by 81 points when reports last came in. The wide-based National Stock Exchange index Nifty was trading at 5205, up by 26 points.Brokers said fresh buying activity picked up on optimism over the global economic recovery and robust December quarter earnings for domestic companies. They added, mixed cues from other Asian markets also influenced the trading sentiments in the domestic market.