Ashley, whose 18-month spell on Tyneside has been beset with difficulties, is willing to sell the Magpies for around £80million.
He paid £134.4m to takeover the St James' Park club in 2007.
"It's been catastrophic for everybody. I've lost my money and made terrible decisions," he told the Sunday Times.
"Now I want to sell as soon as I can. I am genuinely sorry for everybody for what has happened.
"I never said I was an expert in football clubs. I put my money into it and I tried my best, but I accept my best was woefully short."
The Newcastle defender Steven Taylor will miss this summer's European Championship with an Achilles injury. He was the England U21 captain.