The revised proposal includes a "mix and match" facility under which Sportingbet shareholders will have the opportunity to apply to receive proportionately more cash or more shares.
The small print on Sportingbet's 2001 float paperwork reportedly stated that that the directors had been advised that some of the firm's activities violated the federal Wire Act.
The group also confirmed that it would decide by 13 November whether it would make a formal offer, with gaming technology business GVC Holdings, to acquire betting platform Sportingbet.