The Sensex at the Bombay Stock Exchange rose 64 points, or 0.3 percent, to regain the 20,000 level, at 20,006, in opening trade, today. But it later surrendered all its initial gains, and stood 14 points, or 0.1 per cent in the red at 19,927 a short while ago amid some disappointing second quarter earnings by corporate, and weak regional markets.Other key Asian markets in China, Hong Kong, Taiwan, South Korea and Indonesia were down by between 0.5 per cent and 1.5 per cent, today. Over in the US, the Dow Jones Industrial Average had finished 0.1 per cent lower, overnight.