A short statement on the club's official website read: "The board of Newcastle United can today confirm that the club is for sale at the price of £100million.
"The club will not be making any further comment at the present time."
The Swansea City chairman Huw Jenkins has said he disappointed that manager Roberto Martinez is about to leave the club to take charge at Wigan Athletic.Martinez will be unveiled as the new boss of the Premier League side on Wednesday, having made a big impression during his two-and-a-half-years in charge of the Swans.
"He wanted to take up the opportunity of testing himself against what the Premier League had to offer," Jenkins told BBC Sport Wales.
"That's what he based his decision on in the end, he's a very ambitious man."
The former Wales forward John Hartson, who was born in Swansea, has put himself in the frame to replace Martinez at the Liberty Stadium."I would walk over hot coals to take Swansea into the Premier League," he told the Daily Mail.
"I have a lot to give to coaching and management and that is what I want to do."
Watford's chief executive Julian Winter has said the future is bright for the Hornets despite the departure of manager Brendan Rodgers to take charge at Reading last week.
But despite that exit, after just seven months in charge, Winter claims the foundations for the rebuilding of the club remain strong.
"The club won't crumble because of this and we believe we have the right structure to still progress as a football club," he told the club's official website.
"We can move on, the correct structure is there for a new man to come on board and fit into our way of working."
Peterborough United have also held talks with the England U20 international, who has made 25 appearances in the first team for the Premier League Hammers.
The agent of the Leeds United forward Jermaine Beckford has said he will only leave Elland Road to join a Premier League or top Championship club.
The former Scunthorpe loanee is on the transfer list at Leeds after turning down a contract extension.