AMSTERDAM, Sept 21 (Reuters) - Universal Music Group’s shares surged at the start of trading on Tuesday, as the company behind singers such as Lady Gaga and Taylor Swift made its stock market debut. Universal Music Group (UMG) was trading at 25.50 euros by 0705 GMT, up by around 37.8% compared to their reference price of 18.50 euros. UMG’s listing will be Europe’s largest this year and will hand 60% of shares to the shareholders of French media conglomerate Vivendi. UMG is betting that a boom in streaming led by Spotify that has fuelled royalty revenue and profit growth for several years still has a long way to run, in a music industry it dominates along with Warner and Sony Music.