Promoter Eddie Hearn has made Deontay Wilder a final take it of leave it offer worth $12.5million (£8.8m) to fight Anthony Joshua for the undisputed heavyweight title, according to sources in the United States.
The Bronze Bomber holds the WBC title, while AJ unified the division last month vs Joseph Parker and holds the WBA Super, WBO and IBF titles.
The sum would represent a career-high payday for the Alabaman, whose biggest purse to date was $2.1m (£1.5m) against Luis Ortiz in his last fight.
Hearn made the latest £8.8m offer on Tuesday, according to American journalist Adam Abramowitz, though that offer is potentially well below the 40 percent Wilder has publicly admitted he would accept.
The offer was “not considered seriously” with talks still active, but a deal not close.
The fight could generate up to $100m (£71m), the report adds, making the latest offer well below the 60-40 split Wilder craves.