Premier League leaders United have repeatedly said the Old Trafford club was not for sale but its high-yield bonds rose to near record highs on Tuesday on speculation of a deal.
"Qatar Holding is not and has never been in discussions to buy Manchester United football club. There is no truth to the rumours," said the source, speaking on condition of anonymity.
While United have been building a four-point lead in the table as they seek a record 19th league title, off the pitch they have been the subject of media reports saying their American owners, the Glazers, are on the verge of selling up.
The owners are unpopular among many fans with some donning green and gold scarves on match days in protest at the debt the Glazers have burdened the club with.
The colours are those of the Newton Heath works team, United's predecessors, and those wearing them are disillusioned by what they see as exploitation of the club by foreign owners who have raised ticket prices and loaded United with debt.
SURPRISE MOVE
The Glazers, who bought the club in 2005 for about 790 million pounds, surprised fans in November when a source said they had agreed to pay off a 220 million pounds payment-in-kind (PIK) loan from funds outside the club.
A month earlier they had ensured United kept hold of England striker, Wayne Rooney, who had turned the spotlight on the Americans by saying he wanted to leave Old Trafford because the club lacked clout in the transfer market.
Rooney ended up signing a five-year contract after saying he had been convinced to stay because "the management, coaching staff, board and owners are totally committed to making sure United maintains its proud winning history".
Despite what could be seen as moves by the Glazers to court favour with the fans, speculation has been rife that they plan to sell and rumours have centred on Qatar Holding as the buyer.
In January, United denied they had received an approach from Qatar Holding to buy the club and last week a spokeswoman said "The club is not for sale."
Manchester already has Arab owners in town as neighbouring City are owned by Abu Dhabi's Sheikh Mansour bin Zayed Al-Nahyan who has made them the world's richest club and spent hundreds of millions of pounds on players.
The tiny Gulf Arab state of Qatar, the world's largest exporter of liquefied natural gas, in December won the right to host the 2022 World Cup finals.
