Amanda Staveley's bid for Newcastle United was backed by a London-based family, according to a report.
Mike Ashley, the club's owner, this week walked away from takeover talks with Staveley.
The billionaire labelled them a "waste of time".
It had been thought that Staveley, a Dubai-based financier, was using her own money and cash from Middle East-based investors.
But The Guardian have revealed that the Reuben family had pledged money for Staveley's £250m bid, which was tabled in November.
However, billionaires David and Simon Reuben are reportedly no longer involved in Staveley's bid.
Reuben Brothers are leaders in "private equity, real estate investment and development and venture capital", according to their website.
The family's involvement was led by Jamie, David's son, according to the report.
A spokesman for Reuben Brothers told the Guardian: “It is true that we did have a look at it, but nothing actually happened.
"We are not investing in Newcastle United either as Reuben Brothers or as any individuals, including Jamie.”