Mike Ashley has challenged prospective buyers to "show him the money", according to a report.
Former Chelsea and Manchester United chief executive Peter Kenyon is looking for investors to launch a takeover bid for Newcastle United.
Ashley will demand at least £300million for the club, which he put up for sale a year ago.
A source close to Ashley told Sky Sports News that until Kenyon secures funding, it's a case of "a man with no money wanting to buy a football club".
The report adds that buyers "must also prove they have the funds to take the club forward".
Ashley was at St James's Park on Saturday to watch Newcastle's 2-0 defeat to Leicester City.
The result has left the club 18th in the Premier League ahead of Saturday's game against Manchester United at Old Trafford.
Asked about Kenyon's interest in buying United, manager Rafa Benitez said: "I had no idea,” said Benitez. “I have to concentrate on things on the pitch.”