Ratcliffe, founder of chemicals giant INEOS, emerged as one of two leading candidates to purchase the 20-time English champions, along with Qatari banker Sheikh Jassim Bin Hamad Al Thani.
A lengthy takeover saga has followed, with numerous bids entered by both boyhood fan Ratcliffe and Sheikh Jassim, but no progress has been made over any potential change of ownership from the Glazer family, who announced in November they were open to selling the club.
United's valuation on the New York Stock Exchange plummeted last month after reports the Glazers may not sell.
It is now being reported that Ratcliffe could target a minority stake in the Premier League giants.
Sky News said Ratcliffe could seek a stake of about 25 per cent as part of a proposal to try to bring the drawn-out sale process to an end, having initially wanted to complete a majority takeover.
If the Glazers accepted this new reported offer, the American family would retain majority control of the club they bought in 2005.
The Glazers are deeply unpopular with United's supporters, who accuse the family of having saddled the club with debt and not investing enough.
Thousands of fans took part in an hour-long sit-in at Old Trafford after a 3-2 win over Nottingham Forest in August.
United have started the Premier League season poorly, losing four of their opening seven games to sit 10th in the table.