Shares of Manchester United fell as much as 23 per cent on Monday after reports that British billionaire Jim Ratcliffe is looking to acquire only a 25 per cent stake in the football club raised concerns that a buyout by Qatar's Sheikh Jassim bin Hamad al Thani could be off the table.

The shares were last down 10.5 per cent at $17.88 in premarket trading. If losses hold, they could touch their lowest level in more than four months. Ineos Chair Jim Ratcliffe would pay over $1.5 billion for the stake in Manchester United if his bid for the club is accepted by the Glazer family that controls it.

Ratcliffe's bid puts the club valuation close to $6.5 billion, excluding net debt of more than $600 million, the report said, topping a rival offer from Qatar's Jassim for 100 per cent of the Premier League club.

"Investors are clearly reacting with disappointment to expectations the Qatar deal for Manchester United will not go through," said Susannah Streeter, head of money and markets at Hargreaves Lansdown.

"Expectations for a flood of fresh funding into Man U's coffers for a new stadium and new players are being revised."

A large number of fans have been clamoring for a change of ownership because the Glazers have overseen a significant downturn in the club's fortunes, with the club winning just the last of their 20 top-flight titles.

Jassim informed the Glazer family a few days ago that he will not raise his bid of more than $6 billion for Manchester United, which had a market capitalization of $3.26 billion as of Friday's close.

While the stock trades at a premium compared to November 2022, when the Glazer family announced a potential sale or new investments in the club, it has shed about 14 per cent this year with no firm deal outcome.