Premier League champions Manchester City have been accused of manipulating contracts in order to circumvent UEFA's Financial Fair Play (FFP) regulations.
German outlet Der Spiegel claims that it has seen internal documents which suggest that City and their sponsors altered contracts in order to cover up a £9.9m shortfall in 2013.
The shortfall is understood to relate to the sacking of Roberto Mancini that year, with the report claiming that Etihad, Aabar and the Abu Dhabi tourism authority all paid more than had been agreed in order to wipe out the £9.9m sum.
An email from City's chief financial officer Jorge Chumillas allegedly read: "We will have a shortfall of £9.9m in order to comply with Uefa FFP this season. The deficit is due to RM termination. I think that the only solution left would be an additional amount of AD sponsorship revenues that covers this gap."
The report goes on to claim that City owner Sheikh Mansour provided £12m of supplements to existing deals with sponsors in Abu Dhabi as a way to invest more money into the club.
"As we discussed, the annual direct obligation for Aabar is £3m. The remaining £12m will come from alternative sources provided by His Highness," read an email by club executive Simon Pearce in April 2010.
City were found guilty of breaching the FFP rules in 2014 and came to a £49m settlement with UEFA, £32m of which was suspended, while their 2014-15 Champions League squad was also reduced.