Sir Jim Ratcliffe: Prospective owner visits Manchester United
Ineos owner Sir Jim Ratcliffe and Qatari banker Sheikh Jassim will submit improved bids to buy Manchester United before Wednesday's 21:00 GMT deadline.
The two parties, the only publicly-declared bidders, met with United officials this month.
Both are understood to have held positive meetings while visiting Old Trafford and United's training ground.
Ineos want to buy the combined Glazer shareholding of around 69%, but the Qataris are targeting 100% of the club.
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BBC Sport has learned that United officials met eight different potential investors over a 10-day period of high-level meetings recently, including Ratcliffe and representatives of Sheikh Jassim.
The amount of their initial bids have not been disclosed (with reports both are in the region of £4.5bn), but they are clearly far below the £5-6bn valuation that the club's American owners - the Glazers - have established.
Whether they - or any other prospective bidders - are able to submit an offer that persuades the Glazers to sell is the next key question.
If not, and with United's fortunes improving significantly in recent months under manager Erik ten Hag, the Americans may well yet decide to retain the club and perhaps instead look to sell a minority stake to the likes of US hedge fund Elliott Investment Management.
The Glazer family said in November they were considering selling United.
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