Manchester United shares have risen sharply amid speculation that US sports tycoon Malcolm Glazer is about to mount a takeover bid for the club.
The shares jumped 5% on Friday, giving the club a stock market value of £741m.
The Financial Times earlier reported that Mr Glazer had instructed Commerzbank to explore a takeover bid.
The move comes a day after Mr Glazer raised his stake in the club to 16.31%, and after Irish tycoons John Magnier and JP McManus lifted theirs to 28.89%.
According to the Financial Times, Commerzbank is exploring financing options and possible bid structures.
A spokesman for Manchester United said the club had regular talks with Mr Glazer because of his shareholding and would continue to do so.
But he declined to comment on the prospects of a bid.
The owner of the Tampa Bay Buccaneers American football team snapped up 5.4 million shares in the Premiership club on Thursday.
But the move still leaves him way behind the Irish millionaires, whose holding in the group remains just below the 30% mark - which would automatically trigger a full-scale bid under market rules.
However, the pair are involved in an increasingly acrimonious dispute with the club's board over corporate governance at the club.
Meanwhile, Mr Magnier is also fighting a high profile battle against the team's manager, Sir Alex Ferguson, over stud rights for the champion racehorse Rock of Gibraltar.
The FT reported Mr Glazer's representatives are understood to have "offered their help" to the club at the height of the row.
Commerzbank said it had "no comment" to make regarding the reports.