Manchester City have been found guilty of 114 of the 115 financial charges brought against the club by the Premier League.
The verdict, according to The Athletic, was communicated to Premier League clubs following a meeting on Thursday, with City cleared of only one charge.
However, the punishment for the breaches has yet to be determined. The club is expected to appeal the verdict once sanctions are announced.
A Manchester City spokesperson said the Premier League process was still ongoing, with significant elements yet to be completed and subject to strict confidentiality.
The club maintained that it had respected due process and reiterated its position from a February 2023 statement.
The charges relate to alleged breaches of Premier League financial rules between 2009 and 2018. The investigation followed the publication of leaked financial documents concerning the club by German newspaper Der Spiegel in 2018.
The case was subsequently referred to an independent commission, which conducted hearings into the allegations.
Manchester City have consistently denied wrongdoing and maintained that they complied with the relevant financial regulations.
The club has won eight Premier League titles, four FA Cups, seven League Cups and one Champions League under the ownership of Sheikh Mansour.