The Sunday Times claims that Coolmore have written to the O.T. board to question the amount of money paid out to agents when players are bought by United.
The paper quotes one letter to United chairman Sir Roy Gardner as saying: "What we cannot understand is the necessity for the relative secrecy in which agents conduct their role and the astonishing fees which have been charged to the company."
The Sunday Times claim to have seen another letter dated 21st January:
"Once again we invite you to respond providing proper explanations concerning the matters raised and we invite the board to reconsider its position. No further steps should be taken while these matters remain outstanding . . . In the meantime we reserve all our rights as shareholders to take such action as we may be advised."
However, United have dismissed any fears of wrong-doing involving agents.
A club statement said: "All transfer negotiations are conducted by the executive directors of the club with legal advisers. 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 News of The World have another back page story in which they accuse United of paying way over the odds for Ronaldo. They also say that they wrote to United and asked the following questions but just received this reply: "All our transfers are done in accordance with FIFA and FA regulations. There will be no further comment."
The NOTW said their questions included:
Why did United pay so much for Ronaldo?
Why was English agent Tom Hendry elbowed from the deal at the last minute?
Why do United need agents to represent them in deals?
Was Francis Martin, of Elite invloved in the Ricardo deal?
Was anyone from Elite involved in the Saha purchase?
In addition, it appears that politicians want to get involved now. Alan Keen MP told The Sunday Mirror: "We would like to look at all the deals that have made the news recently.
"Agents seem to be one of the most unsavoury aspects of the game and I have not met anyone in football who is in favour of them.
"We want the authorities to put it right and we need as much transparency in the game as possible."