The latest developments on one deal are so sensitive that it has not been identified.
Allardyce Has Most To Lose In Inquiry
Graeme Souness says he will clear his name in court, Portsmouth boss Harry Redknapp remains damaged by the revelations, but Allardyce is the one who could suffer the most.
Quest's report recommended further inquiries into the apparent conflict of interest which existed when Allardyce's son, Craig, was involved in transfers at Bolton. And it is understood solicitors for Allardyce are considering a request for their client to be re-interviewed about up to four deals, involving Julio Correa, Ali Al-Habsi, Blessing Kaku and Tal Ben Haim.
Now Allardyce also faces having to explain in court how Bolton came to sign Israel international Idan Tal last year.
Unlicensed Israeli agent David Abou has launched legal action against Craig Allardyce in a bid to receive half the £135,000 commission he negotiated for himself from Tal's free transfer.
Top sports lawyer Mel Goldberg, of Max Bitel, Greene, who is representing Abou, confirmed "letters before action" had been sent out to Craig Allardyce and Bolton.
Goldberg said: "If we do not receive a satisfactory response, legal proceedings will be issued."
Sam Allardyce would be a key witness if the case against his son reached court.
Four transfers involving Newcastle remain uncleared by Quest.
The Mail report: "Sources indicate that Shepherd Snr, despite striking a deal with Ashley to stay on as chairman after selling his family's 28 per cent holding for £37m, may not stick around much longer to support the manager he appointed.
"It is also understood that Allardyce would not have been the new owner's first choice as manager and that the bad publicity about the Bolton transfers, on top of Ashley's problems with his own company, Sports Direct, has not impressed him.
"If Allardyce thought his move to Newcastle would draw a line under the past and herald a glorious new chapter of his career, he was mistaken. The Quest report, came back to haunt him in a potentially far more damaging way. And there is every sign that they will continue to do so for some time to come."