Manchester United have denied any wrongdoing in transfer negotiations after the club's leading shareholders reportedly questioned recent deals.
Ferguson has yet to sign a new deal
The Sunday Times newspaper claims John Magnier and JP McManus have written to the board to challenge the amount of money paid out to agents.
The Irish billionaires are also said to have demanded that United stop contract extension talks with Sir Alex Ferguson.
But United said in a statement: "All transfer negotiations are conducted by the executive directors of the club with legal advisers."
It added: "In common with all football clubs, we often work with Fifa-registered agents.
"Any fees to agents are disclosed to the Premier League and, with effect from
the current transfer window, to the Stock Exchange."
The transfers of Brazilian international Kleberson and American goalkeeper Tim Howard have come under scrutiny in recent weeks.
But Premier League chief executive Richard Scudamore believes United counterpart David Gill has adopted the right strategy by disclosing details of Louis Saha's move to Old Trafford.
"The reality is we
record, as do the FA, all transfer dealings and we know exactly who the money
goes to in the first instance," Scudamore told BBC Radio Five Live.
"Actually the right way of managing it in some ways is for shareholders to
question and challenge what is happening to funds.
"I think David Gill has made a major step forward this week in the Saha deal
in actually telling everybody exactly who got what for that deal.
"Any evidence we get we take a look at, we make sure it is being done
appropriately. That's not to say we have any view as to the right and wrong
amounts of money involved in transactions."
United manager Ferguson is currently engaged in legal action against Magnier over racehorse stallion Rock Of Gibraltar.
Ferguson's ongoing dispute with Magnier - over the stud rights to Rock of Gibraltar - has prompted speculation that the Scot's new deal could be in jeopardy.
But United chief executive Gill insisted on Sunday that Ferguson was on the verge of signing a new contract, which would keep him at the club until 2007.
Gill said: "We are very close; the final details are with the lawyers."
Ferguson has been in negotiations with United for months, but is still to sign an extension to his present deal.
Shareholders United, the non-political group for fans holding one or more
share in the club, have given their full backing to Ferguson in the matter.
Spokesman Oliver Houston said: "Sir Alex is undoubtedly one of the club's and
the company's best assets.
"It would be a disgrace if personal score-settling, bullying and dirty tricks
were allowed to win the day."