New documents show that the North East club's owner Mike Ashley has entered a charge agreement with potential buyer Amanda Staveley, whose bid involves the Reuben Brothers and Saudi Arabia's sovereign wealth funds.
A 31-page document has been lodged at Companies House, and it lays the legal groundwork for the proposed deal.
The dossier also includes details of a £150m claim related to the financier's company PCP Capital Partners, and the firm's legal case against Barclays Bank PLC.
Meanwhile, BBC Sport notes that the Premier League which has been informed of the plans - have started carrying out checks under the league's owners and directors test.
Ashley - who took over back in 2007 has proven divisive with Newcastle fans, with supporters accusing him of a lack of ambition.
Regarding the update, sports finance expert Kieran Maguire commented: "These are steps you'd expect to take place in respect of a takeover, it seems that things have accelerated.
"The trouble with Mike Ashley is that until you see the final documents, it's never completed but the other parties would not waste their time like this unless there had been progress in terms of a takeover."