The Sensex at the Bombay Stock Exchange shot up 227 points, or 1.3 percent, to cross the 18,000 point level after two weeks, at 18,041, in early trade, today, on sustained buying by funds and retail investors, amid positive global markets. Later, the Sensex trimmed some of its initial gains, to stand 101 points, 0.6 percent in positive territory, at 17,914 in afternoon deals, a shor while ago. The 30-share Sensex had gained more than 660 points in the past three trading sessions.Other key stock indicces in Japan, Indonesia, Singapore, South Korea and Taiwan were up by between 0.4 percent and 1.5 percent, today. Across on Wall Street, the Dow Jones Industrial Average had jumped 1.7 percent, overnight, to its highest level since December 2007.