Shares of Sun Pharmaceutical Industries continued to gain momentum for the fifth straight session, surging nearly 5 per cent to Rs 427.65 on the Bombay Stock Exchange (BSE) on Monday after Morgan Stanley 'double upgraded' the stock on hopes of earnings revival. In the last one week, Sun Pharma share price has rallied over 15 per cent, as against to 0.37 per cent decline in the Indian benchmark index BSE Sensex.