Erasing early gains, the Bombay Stock Exchange benchmark Sensex tumbled by over 98 points at mid-session on Wednesday on emergence of selling by funds in stocks led by information technology segment after the rupee rose to the highest in more than a year. The Sensex, which rose by 162 points at the outset, fell to show a loss of 98 points to 16,860 at 1 PM with stocks of Infosys, Tata Consultancy and Wipro recording fresh losses. More than 50 per cent of the Indian software export business comes from the US markets.