Steel Authority of India Ltd's (SAIL's) market capitalisation crossed Rs 50,000 crore for the first time today as the stock touched an all time high.The scrip touched Rs 124 on the Bombay Stock Exchange and then finally closed at Rs 122.75. Volumes on BSE were at 5,241,971 shares and on NSE at 20,651,142 shares. SAIL's total share capital is Rs 4,130.40 crore. Market sources attribute the rise to higher steel prices in the coming months and a best-ever financial performance from the PSU.