The BSE benchmark Sensex shed over 146 points in opening trade today, continuing its losing streak for the fifth day in a row on sustained selling triggered by poor second quarter corporate earnings and a weak trend on other Asian bourses.The 30-share BSE index, which has lost over 686 points in the past four sessions, declined by 146 points, or 0.86 per cent, to 16,736 in opening trade.In a similar fashion, the wide-based National Stock Exchange Nifty index fell by 38 points, or 0.76 per cent, to 5,029.Meanwhile, in the Asian region, Hong Kong's Hang Seng Index fell by 1.94 per cent, while Japan's Nikkei Index shed 0.72 per cent in early trade today.