Anthony Joshua wants to “see the money” before agreeing to Deontay Wilder’s $50m (£35.9m) unification fight offer, says promoter Eddie Hearn.
American heavyweight Wilder posted a video on Twitter showing WBO, IBF and WBA titles holder Joshua, 28, saying he would accept the fight for $50m.
But Hearn said he must be convinced the money “exists” before agreeing to the bout “in either London or Vegas”.
The offer came via an email directly from WBC champion Wilder, said Hearn.
In a video interview on Wednesday, Hearn also said:Previously Wilder, 32, said “all the money is in the bag so I expect you will be a man of your word”.
Wilder’s manager Shelly Finkel confirmed to ESPN that an offer had been made.
Finkel also said the offer contains no rematch clause and that it would be the next fight for each boxer, taking place between September and December at a venue of Wilder’s choosing.
“It’s a great move from Deontay. It makes everyone say: ‘You’ve got to take the fight now’,” added Hearn.
“We really want to do the fight in the UK because we’ve built something special there.
“But if there’s substantial money to do it elsewhere we will definitely look at it. In my opinion it’s got to be in the UK or possibly Vegas.
“It’s not a case of we sign the contract and they go and raise the money. If you’ve got it – show us it and then we can talk.
“I spoke to AJ – he knows the situation but we want to know if it’s real. We want to see the money and know were it is.
“There’s a real strong chance this fight could happen – we’re not looking to be difficult.”
Hearn said earlier this month that the WBA has ordered the Briton to enter into negotiations with mandatory challenger Alexander Povetkin.
Wilder added: “Tell Eddie Hearn to let you personally check his email this time. By the way, I sent your manager Rob McCracken the email as well.
“I am looking forward to our meeting in the ring.”
Unbeaten Joshua added the WBO belt to his collection after a unanimous points win over Joseph Parker in Cardiff on 1 April, while Wilder beat Luis Ortiz in his last fight in March.