Metal stocks are the top sectoral gainers in trade while PSU stocks also posted strong gains on Wednesday.The metal stocks index is up 2.8 per cent. SAIL is up 7 per cent, NMDC is up 5 per cent, while JSW Steel is up 3.7 per cent intra-day.The benchmark BSE Sensex is trading at 73,978 points, up by 240 points.