The Sensex at the Bombay Stock Exchange closed with a marginal loss of 2 points, at 16,254, today, even as the Economic Survey, unveiled a day before the Union Budget, was optimistic about economic growth. The Nifty at the National Stock Exchange managed to gain 1 point, at 4,860.Stock markets in Japan, Singapore, Hong Kong, and South Korea fell between 0.3 percent and 1.5 percent, on concerns about the credit rating of Greece.