Mumbai (PTI): Shrugging off early gains, the Bombay Stock Exchange benchmark Sensex on Wednesday nosedived over 692 points midway to dip well below the psychological 10,000 point level, on heavy selling by funds after reports of Satyam Computer Services Chairman resigning.

The Sensex, which commenced the day higher by 133.79 points, dropped by 692.37 points, or 6.70 per cent, to 9,643.56 at 1245 hrs, as the index-linked Satyam Computer plunged to Rs 52.65 from yesterday's close of Rs 178.95.

Last night Satyam's ADR was higher by four per cent on the Nasdaq.

Selling pressure began after reports that Satyam Computer Services Chairman Ramalinga Raju tendered his resignation, ahead of the crucial January 10 Board meeting.

With mounting selling pressure, the 50-share National Stock Exchange's index Nifty dropped by 201.00 points, or 6.45 per cent, to 2,911.00 at the same time.