The BSE benchmark Sensex lost over 37 points in opening trade on Monday as funds and retail investors adopted a cautious wait-and-watch strategy in the absence of positive cues. The 30-share barometer, which fell by 56.28 points in the previous session, moved down further by 37 points, or 0.20 per cent, to 18,525 within the first few minutes of trade. Similarly, the wide-based National Stock Exchange Nifty index declined by 15.50 points, or 0.28 per cent, to 5,566. In other markets in Asia, Hong Kong's Hang Seng index was trading 0.07 per cent higher, while Japanese financial markets are closed for a public holiday.