The Magpies have described the claims of a multi-million pound price-tag as 'absolute nonsense'.
A national newspaper report suggested a United States private equity fund - InterMedia Partners - had been told the club was available for £420m, some £286m more than billionaire Ashley paid for it a year ago.
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However, a club spokesman said: "It is absolute nonsense."
It was reported informal discussions between representatives of Ashley and counterparts from the New York-based outfit took place.
This is not the first time the the club's ownership has been questioned.
In the past, the word from St James's Park was that Ashley is building for the future and is not in it to make a quick profit.
However, that has not stopped repeated talk in the City, and now further afield, that the business is for sale at the right price.
Ashley installed long-time associate Derek Llambias in the new role of managing director last month following Chris Mort's departure as chairman.
The pair are currently overseeing the club's summer recruitment drive with executive director (football) Dennis Wise and vice-president (player recruitment) Tony Jimenez having provided manager Kevin Keegan with new signing Jonas Guiterrez earlier this week.
But the club has undergone radical change in the last 12 months or so.
Former chairman Freddy Shepherd had already fought off a series of potential takeover bids when Ashley made his move last summer, eventually securing a £134.4m buyout with the minimum of fuss.
He has since ploughed around £100m into the club to address the debt he inherited and to strengthen the squad.
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