Erasing all its initial gains, the Sensex at the Bombay Stock Exchange had lost a hefty 315 points, or 1.7 percent, to 18,369, in afternoon trade, a short while ago. The Sensex fell on across-the-board selling pressure, and especially in consumer durables, realty and auto stocks. Earlier, in the morning, however, the Sensex had managed to gain a modest 36 points, or 0.2 per cent, to 18,721, on bargain hunting by investors. The Sensex has already lost 467 points in the last two trading sessions.Elsewhere in Asia, the Japanese market led the decline in the regional bourses, after Standard & Poor's cut Japan's credit rating. So the key benchmark indices in Japan, Hong Kong, Indonesia and South Korea were down by between 0.3 percent and 1.2 percent.