Erasing initial gains, the BSE benchmark Sensex was trading 101 points in the negative territory at 18,553 when reports last came in. The 30-share index, which gained 147 points in Tuesday's trade, moved up by 112 points, or 0.59 per cent in green, to 18,766 points in opening trade.In a similar fashion, the wide-based National Stock Exchange Nifty index was trading 29 points in red at 5,585.