The club confirmed on Tuesday that Barry Moat has failed to meet Ashley’s £80million asking price for the club.
Ashley bought the club in 2007 for around £134.4million.
Ashley now plans to sell naming rights to St James’ Park to increase revenues.
A Newcastle statement on Tuesday said: “Mike Ashley is totally committed to the future success of Newcastle United and will be focused on gaining promotion back to the Premier League. Mike will put a further £20m into the club this week.”
Chris Hughton was also confirmed as the club’s permanent manager on Tuesday.
“Whilst confirming these two matters, Newcastle United now aims to move forward on and off the pitch,” the statement continued.
“The club aims to maximise its commercial revenues; this includes renegotiating its club sponsor and kit deal, which expire at the end of this season, as well as welcoming offers for the stadium naming rights for next season.”