Ineos chief executive Jim Ratcliffe is looking to invest $300 million (£245 million) in Manchester United's infrastructure, in addition to his $1.5 billion plus offer to buy a 25 per cent stake in the club, according to a person familiar with the matter.
The investment, intended for upgrading the club's ageing infrastructure, will be financed by the billionaire personally and not add to the Premier League club's existing borrowings, the source said.
Shares in United rose 4 per cent to $18.85 on the news, which was first reported by Sky News.
Ratcliffe did not immediately respond to a request for comment. Manchester United declined to respond to a Reuters request for comment.
Reuters reported in October that Ratcliffe would pay more than $1.5 billion for a 25 per cent stake in United were his bid for the iconic club to be accepted by the Glazer family that controls it.
The Glazers have not yet reached a deal with Ratcliffe, but one is expected to be finalised between the two sides in the coming weeks, the source said.
Qatar's Sheikh Jassim bin Hamad al Thani, the rival bidder for the club, told the Glazers last month that he would not be raising his $6 billion bid further and had dropped out of the bidding process, Reuters has previously reported.
Ratcliffe founded Ineos in 1998 and is the chemical group's chairman and chief executive officer, with a two-thirds stake. Forbes pegs his net worth at about $19 billion.
The British billionaire is no stranger to the business of sports. Ineos owns French Ligue 1 club Nice, Swiss Super League side FC Lausanne-Sport, and works with Racing Club Abidjan of Ivory Coast Ligue One. It is also behind the Grenadiers, one of the world's most successful cycling teams.
Record 20-time English champions, United have more than 650 million fans worldwide, according to market research firm Kantar.
But a large number of them have been clamouring for a change of ownership because the Glazers have overseen a significant downturn in the team's fortunes.
United won the League Cup under Erik ten Hag last season, but their third-place finish in the Premier League, 14 points behind local rivals and treble winners Manchester City, underscores the scale of the turnaround required.