The domestic stock markets have a gap-up opening, buoyed by the strong closing on Wall Street on Wednesday after the Federal Reserve said that the US economy is heading for its strongest growth in nearly 40 years. At 9:25 am, the BSE Sensex is trading at 50,219.85, higher by 422 points or 0.82 per cent and the NSE Nifty is at 14,850.75, up 132.15 points or 0.85 per cent.