As previously reported, Eddie Hearn has labelled Deontay Wilder's $50 million offer to Anthony Joshua for a heavyweight unification fight as a "PR move" and said "we can't afford to accept a deal that doesn't exist."
WBC champion Wilder on Wednesday posted a video on social media announcing he had something in the mail for Joshua – a $50 m offer.
Hearn, who is in New York for talks with the Wilder camp on Friday, acknowledged he received an email from Wilder confirming the big-money pledge, but Joshua's promoter will not take it seriously until he has proof the funds are in place.
"I got an email from Deontay Wilder, basically offering a 50/50 split of the fight, which isn't of interest, but with a 50 million guarantee which is of interest," Hearn told iFL TV.
"It said to please respond by tomorrow, which makes it feel like a PR move, especially since it has come from Deontay. But we have to take it seriously.
"If this is serious, with a proof of funds and proper contract, we need to look at it."
Hearn added: "We really want to do the fight in the UK. That's where we've built something incredible and the base of our offer was doing it in the UK.
"But this is substantial money, and if there is something there then we will definitely look at it.
"No disrespect to Deontay but I don't believe he has that kind of money so I want to know where it's coming from and who is paying it. We can't afford to accept a deal that doesn't exist."
Hearn said that there is no chance that a deal will be struck before the end of the week.
"Not this weekend, but if the money is there and the venue is to our liking, the money is secure and the other rights are taken care of there is a real strong chance this fight could happen," Hearn said.
"There is still a chance in other ways, with our offers or splits, but this is something that we have to take seriously, if it is serious.
"We won't know that until we have the meeting or we some paperwork, i.e. an offer from someone who is going to pay the money and a contract with actual proper terms with what they require from Anthony Joshua."