Giving up all its initial gains, the Sensex at the Bombay Stock Exchange stood 126 points, or 0.7 percent in negative territory, at 18,932 on profit-booking by investors, after recent strong gains, a short while ago. Earlier in the morning, however, the Sensex had opened 28 points, or 0.2 per cent higher, at 19,086, following the government unleashing a second wave of economic reforms. The Sensex had gained almost 490 points in the past four trading sessions.Other Asian markets in Japan, Hong Kong, Indonesia, Singapore, South Korea and Taiwan had posted gains of upto 0.8 percent, today. Across on Wall Street, the Dow Jones Industrial Average had ended 0.6 per cent higher in yesterday's trade.