However, English champion City insisted the accusations against it are false and that it welcomed the opportunity to clear its name, AFP reported.
German magazine Der Spiegel, using material purportedly obtained from the whistleblowing outlet Football Leaks, alleged in November that City had set up sponsorship deals to circumvent regulations limiting how much money owners can put into a club.
“The Investigatory Chamber of the independent UEFA Club Financial Control Body has today opened a formal investigation into Manchester City FC for potential breaches of Financial Fair Play (FFP) regulations,” said a UEFA statement on Thursday.
“The investigation will focus on several alleged violations of FFP that were recently made public in various media outlets.”
City responded immediately by saying it supported the investigation and that it had nothing to hide.
“Manchester City welcomes the opening of a formal UEFA investigation as an opportunity to bring to an end the speculation resulting from the illegal hacking and out of context publication of City emails,” the club said in a statement.
“The accusation of financial irregularities are entirely false. The club’s published accounts are full and complete and a matter of legal and regulatory record.”
City had earlier responded to Der Spiegel’s claims by saying there had been an “organized and clear” attempt to damage the club’s reputation.
A ban from UEFA competitions, including the Champions League, is a potential punishment if City are found guilty of FFP breaches.
City was fined €60 million ($67.3 million) and subjected to squad, wage and spending caps in a 2014 settlement agreed with UEFA following a previous breach of the rules.
City coach Pep Guardiola has always insisted that City would accept a ban but does not believe it is likely after discussions with the club’s UAE owners.
“We will not be banned, no. That’s what I think because I trust in my chairman, with my CEO, what they have explained to me,” he said.
“If it happens, because UEFA decide that, we will accept it and move forward.”
City is not the only European heavyweight to be caught up in claims of breaking financial fair play rules.
French champion Paris Saint-Germain quashed reports it could be forced to sell either Kylian Mbappe or Neymar in a bid to circumvent eventual FFP sanctions.
Qatar-owned PSG, which splashed a combined total of more than €400 million in 2017 for Brazil star Neymar and France World Cup winner Mbappe, blasted allegations as “totally false and ridiculous”.
Former European champion AC Milan was warned in December that it risks being excluded from European competition if it fails to “break even”.
Milan had already been banned for a year from the Europa League due to breaching FFP regulations before winning an appeal to the Court of Arbitration for Sport (CAS) last year.
But UEFA said the former seven-time European champion again faces suspension from continental competition in future seasons “should the club not be break-even compliant at 30 June 2021”.