The Sensex at the Bombay Stock Exchange gained 76 points, or 0.4 percent, to close at 17,633, on fag-end buying by investors, today. The Nifty at the National Stock Exchange rose 28 points, or 0.5 percent, to 5,348.But stock markets in Japan, China, Hong Kong, and South Korea lost between 0.1 percent and 1.5 percent.