The Sensex at the Bombay Stock Exchange tanked 434 points, to slip below the 16,000 mark, at 15,790 in early trade, today, in line with tumbling global markets. Remaining weak, the Sensex stood 427 points, or 2.6 percent in the red, at 15,798, a short while ago. Stock markets in Japan, China, Hong Kong, South Korea, Singapore and Taiwan were down between 1.8 percent and 4.2 percent, today, as European sovereign debt worries, and an unexpected increase in US jobless claims stoked concerns about the strength of the global economic recovery.A key Wall Street index, the Dow Jones Industrial Average, had plunged 2.6 percent, overnight.