Deontay Wilder will reportedly confirm in the next 48 hours whether he intends to fight Anthony Joshua after being offered a flat fee of £8.8m.
Talks have been ongoing between the two camps to stage a heavyweight unification bout later this year, likely to be held somewhere in the United Kingdom.
According to The Telegraph, three separate offers have been submitted to Wilder this week for a fight expected to gross at least £60m if it goes ahead.
However, the same report indicates that the contract does not state when the fight will be, or whether in fact it will even be Joshua's next bout.
As part of the agreement, a 50/50 split in the purse may be discussed for a second contest between the pair.