Qatari banker Sheikh Jassim Bin Hamad Al Thani has submitted an improved fifth and final bid for Manchester United and wants an answer by Friday.
Sheikh Jassim is in a bidding war with British billionaire Jim Ratcliffe after the pair emerged as the main contenders to buy the Premier League club.
United announced in November that the board was exploring "strategic alternatives to enhance the club's growth", with a full sale one of the options.
Current owners, the Glazer family, are understood to value United at £6 billion and the Raine Group was brought in to oversee the process.
The fifth offer, submitted in the last week, remains for 100 per cent control of the club.
There has been no indication when the Glazers will make a decision over the potential sale.
But Sheikh Jassim has set Friday as a deadline to make headway in discussions, according to sources close to the bid.
While the latest offer is expected to remain on the table after that point, the end of the week would mark the end of Sheikh Jassim's engagement with the process.
INEOS chemical company founder Ratcliffe appeared to be the front runner after a third round of bidding closed in late April.
Ratcliffe, a boyhood United fan who failed in his attempt to buy Chelsea last year, reportedly wants to purchase a controlling stake of more than 50 per cent.
That would allow the Glazers to remain involved – a move that would be deeply unpopular with supporters.
United lost Saturday's FA Cup final to Manchester City but they ended a six-year trophy drought by winning the League Cup and finished third in the Premier League in Erik ten Hag's first season in charge.
The lengthy ownership saga means there is an air of uncertainty over the future of the club as they prepare for an important summer transfer window.
Co-owner Avram Glazer was at Wembley for Saturday's 2-1 defeat by City and ignored questions about the takeover as he left through the interview area.
Asked about the potential takeover and summer improvements, United boss Ten Hag said: "I think in this moment I don't want to discuss that.
"It's about finalising the season. We have to be quiet, analyse the season, go into the depth, then set the right conclusions and then take action."