The Investigatory Chamber of the independent UEFA Club Financial Control Body has opened an investigation to probe allegations about Manchester City's breach of Financial Fair Play regulations.
German Der Spiegel magazine claimed that the club has bypassed FFP rules by inflating sponsorship deals.
"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," reads a statement issued by the English football club.
"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."
If found guilty, Manchester City could face a potential ban from the Champions League.