LONDON: Shares in English soccer giant Manchester United slipped in volatile trading on the Frankfurt Stock Exchange on Monday, following media reports the club was set to replace its manager with former Chelsea boss Jose Mourinho.

Manchester United's main stock market listing is in New York, although it has a secondary, and less widely traded, share listing in Frankfurt.

The Premier League club's Frankfurt-listed shares briefly opened up 2.4 percent, but then slipped back to stand 2.5 percent lower.

Manchester United's shares closed up 2.4 percent in New York on Friday.

British media reported that Mourinho, 53, would take over at Manchester United even though Dutchman Louis van Gaal, who steered United to an extra-time FA Cup final win over Crystal Palace on Saturday, had a year left on his contract.

Mourinho, sacked by Chelsea in December after his second spell in charge of the west London club, has also managed Porto, Inter Milan and Real Madrid, winning Europe's premier Champions League tournament with both Porto and Inter Milan.

Manchester United was bought in 2005 for about 800 million pounds by the Glazer family, owners the Tampa Bay Buccaneers franchise in the National Football League.

Shares in Manchester United were listed on the New York Stock Exchange in 2012 in an initial public offering.

According to Thomson Reuters data, the Glazers’ Red Football LLC investment vehicle has a 20 percent stake in the club's New York-listed shares.

US investment firm Baron Capital Management, Lansdowne Partners, Jupiter Asset Management and Fidelity are among other major institutional investors.

The New York-listed shares have fallen by around 6 percent so far in 2016.

Earlier in May, Manchester United reported record third-quarter revenues and higher earnings.

However, van Gaal's failure to qualify for the Champions League is likely to have proved costly.

Manchester United said earlier this month that not getting into the Champions League would cost it more than 30 million pounds ($43.5 million) in revenue next season.