Sir Jim Ratcliffe was at Old Trafford on Friday to attend a presentation held by senior Manchester United management staff.
INEOS founder Ratcliffe and Qatari banker Sheikh Jassim Bin Hamad Al Thani have made offers to buy United to American merchant bankers Raine, which was brought in to assist the club in assessing bids.
The club’s owners, the Glazer family, announced last November they were conducting a strategic review, with the sale of United one option being considered.
Ratcliffe, the 70-year-old owner of Ligue 1 club Nice, was joined at Old Trafford by INEOS co-owners Andy Currie and John Reece.
Former British Cycling chief Sir David Brailsford, now director of sport at INEOS Sport, was also part of the delegation.
Sheikh Jassim’s representatives were in Manchester on Thursday for a tour of Old Trafford before attending presentations at United’s Carrington training complex.
The PA news agency understands Sheikh Jassim’s team visited for 10 hours – far longer than expected – and remain committed to buying the club following the substantive talks.
Sheikh Jassim and Ratcliffe are the only interested parties to publicly announce their bids to Raine.
Elliott Investment Management has also reportedly made it through to the second stage of the process, although the firm is said to be offering funding rather than a takeover.
It is understood Elliott representatives attended the 4-1 Europa League win against Real Betis at Old Trafford on March 9.
United will be holding a press conference to preview their FA Cup quarter-final against Fulham at Carrington on Friday lunchtime while the INEOS visit is taking place.