The Premier League said on Tuesday that Manchester City have been found guilty of serious breaches of the Premier League's financial rules over a nine-season period between 2009 and 2018.
City were found to have arranged sham contracts with a number of commercial partners to artificially inflate the club's revenues, concealing the true state of their finances and avoiding breaches of Premier League's and UEFA's spending limits.
An independent commission also found the club guilty on the majority of charges in relation to their failure to co-operate with the league's investigation.
No sanction has yet been imposed and City said they will appeal against the decision.
"The core decision establishes the facts of what happened at Manchester City during this period. It details how the club systematically broke Premier League rules for nearly a decade," said Premier League chairman Richard Masters in a statement.
"Now we have the commission's decision, we are committed to moving swiftly through the remainder of the process, to provide certainty for the league, our clubs and fans."
Since a 2008 takeover from Sheikh Mansour bin Zayed al-Nahyan, vice-president and deputy prime minister of the United Arab Emirates, City have become the Premier League's dominant force.
They have won eight Premier League titles, four FA Cups and seven League Cups over the past 15 years and also won the Champions League for the first time in 2023.
But that same year they were charged by the Premier League following an investigation into alleged breaches of rules.
A hearing by an independent commission started in September 2024 and concluded three months later.
"Manchester City FC will now pursue the appeal avenues open to it, on the basis that the opinion contains clear material errors, of law, principle and fact, and is unsafe," the club said in a statement.