Falling for the third straight session, the Sensex at the Bombay Stock Exchange lost 97 points, or 0.5 percent, to close at 19,449, after volatile trade, today, on continued selling by investors, ahead of the expiry of the monthly derivatives contracts. The Nifty at the National Stock Exchange shed 35 points, or 0.6 percent, to 5,834.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.