The Sensex at the Bombay Stock Exchange fell 55 points, or 0.3 per cent, to 18,447, in early trade, this morning, on continued selling by investors, after lackluster first quarter earnings of some companies, and amid subdued global markets. After briefly rebounding into positive territory, the Sensex later once again lost ground, and stood 53 points, or 0.3 percent in the negative zone, at 18,449, in volatile trade, a short while ago.Other Asian markets in Japan, Singapore, Taiwan, China, Hong Kong and South Korea were trading mixed, today, as investors awaited signs of progress on Europe's sovereign-debt crisis. Across on Wall Street, the Dow Jones Industrial Average had fallen 0.1 per cent overnight.