Sun Pharmaceuticals shares gained over 4 per cent on Wednesday after Bank of America Merrill Lynch (BoA-ML) upgraded the stocks of pharma major to "buy" from "neutral". Share price of the pharma major closed 4.32 per cent higher at Rs 927.25. The global investment bank cites integration with Ranbaxy, price hikes at unit Taro and improvement in US supplies as key reason for the upgrade. BoA-ML upgraded the target price to Rs 1060 for Sun Pharma shares from Rs 960 earlier. Manoj Garg, analyst, BoA-ML said, "Sequential improvement in ex-Taro US business, including supply from Halol, is positive; expect further improvement post the completion of remedial measures at Halol." (With inputs from Reuters)