The Glazer family reportedly met with representatives of the investment group, which represents the Qatari royal family, last month.
Discussions, however, are said to have stalled because of a dispute over the club’s value, The Sunday Times reported.
The Glazer family are demanding £2bn for the Premier League leaders but Qatar Holding, which recently signed a £125m shirt sponsorship deal with Barcelona, is only willing to pay £1.5bn.
Manchester United denies that the club is for sale.
A spokesman says: “There has been no approach of any kind to buy the club, and one would not be welcome anyway because it is not for sale.”
Rumours that the Glazers are willing to sell the club began in November after they cut the club’s debt by paying off £220m in high-interest PIK loans, making the club more attractive to potential suitors.
Clearing the debt reduced the club’s burden to £526m but has not satisfied fans groups such as the Manchester United Supporters Trust, which is angry with the debts that the Glazers have saddled the club with.