Giving up some of its initial gains, the Sensex at the Bombay Stock Exchange stood a modest 24 points, or 0.1 percent in positive territory, at 21,057, a short while ago, amid the monthly expiry in the derivatives segment. Earlier in the morning, the Sensex had gained 54 points, or 0.3 per cent, to 21,087. Elsewhere in Asia, stock markets in Japan, China, South Korea and Singapore were trading mixed.