Snapping a three-session rally, the Sensex at the Bombay Stock Exchange lost 111 points, or 0.6 per cent, to 18,020, on Monday, on investor caution ahead of the Reserve Bank's credit policy review and some key corporate results. The Nifty at the National Stock Exchange slid 31 points, or 0.6 percent, to 5,419. But stock markets in Japan, China, Hong Kong and South Korea gained between 0.1 percent and 0.8 percent