Paris: Shares in Universal Music, the world´s biggest label with a lineup of megastars from The Beatles to Taylor Swift, surged on its stock market debut Tuesday, giving the company a valuation exceeding $50 billion.

With shares leaping from 18.50 euros to over 25 euros ($29), the US-based music giant found itself valued at EUR 46.3 billion ($54.3 billion) in early trading.

That is way above the $39 billion valuation it was given the night before its listing on the Euronext Amsterdam index.

Trade magazine Music Business Weekly said it had been "expecting an impressive opening for UMG on the Amsterdam Stock Exchange today -- but even we weren´t expecting this."

Universal Music Group (UMG), with its catalogue of four million titles, was floated by its owner, the French media conglomerate Vivendi.

With Vivendi shedding a majority stake in its crown jewel, its own shares sank by more than 15 percent on the Paris CAC 40 stock exchange.

Vivendi is owned by French billionaire Vincent Bollore, who has positioned himself as a powerful right-wing media baron in recent years and is looking to focus more on TV, advertising and publishing.

- Risky move -

Universal Music, like its rivals Warner and Sony, was once threatened by music piracy but profits have soared in the age of streaming.

Analysts say the industry has been undervalued, with JPMorgan Cazenove estimating that UMG´s true worth could go as high as $64 billion, according to Music Business Weekly.

It is home to many of the world´s biggest music stars, from Lady Gaga to Kanye West to Metallica.

Last year the group bought Bob Dylan´s entire song catalogue for $300 million, one of the biggest acquisitions in music history.

Based in Santa Monica, California, UMG has been a cash cow for Vivendi´s media empire, with a turnover of 7.4 billion euros last year, accounting for 46 percent of the parent company´s revenue.

Vivendi is keeping a chunk of UMG, but has already sold off a 20 percent stake to Chinese tech firm Tencent and 10 percent to US financier Bill Ackman.

Aware that shedding its number one asset might be a risky move, Vivendi has taken steps -- described as "quite extraordinary" by one activist shareholder -- to protect its own share price.

It secured agreement from its investors for a massive buyback of up to half its shares following the UMG flotation.

Although that did not stop Vivendi shares from falling on Tuesday, it is designed to give the group cash reserves to fight off any hostile takeover bids.