Chelsea have agreed a resolution with UEFA that will see them hand over €10 million ($11 million) after owning up to "incomplete financial reporting" under the Roman Abramovich regime.
A new ownership group led by Todd Boehly and Clearlake Capital completed their takeover of the club in May last year from Abramovich, who was sanctioned over his links to Russia president Vladimir Putin.
UEFA, which has also banned Juventus from competing in the Europa Conference League this season due to financial irregularities, confirmed it was approached "proactively" by the Boehly-led consortium.
They detected instances of partial financial information being submitted in historical transactions occurring between 2012 and 2019, breaching UEFA Club Licensing and Financial Fair Play regulations.
A UEFA statement said: "Following its assessment, including the applicable statute of limitations, the CFCB (Club Financial Control Body) First Chamber entered into a settlement agreement with the club which has agreed to pay a financial contribution of €10 million to fully resolve the reported matters."
The sanction represents another blow for Chelsea's current owners after a disappointing first year at the helm, with the club's 12th-place finish in the Premier League last term their worst since 1993-94.
Chelsea have forked out around £600 million ($770 million) in transfers since Boehly's arrival, while former Tottenham boss Mauricio Pochettino has been tasked with turning around their on-pitch fortunes.
Chelsea said in a statement the owners became aware of potential impropriety when carrying out a "thorough due diligence process" prior to the purchase and, upon completion of the takeover, they reported this to UEFA.
The statement added: "In accordance with the club's ownership group's core principles of full compliance and transparency with its regulators, we are grateful that this case has been concluded by proactive disclosure of information to UEFA and a settlement that fully resolves the reported matters.
"We wish to place on record our gratitude to UEFA for its consideration of this matter. Chelsea greatly values its relationship with UEFA and looks forward to building on that relationship in the years to come."
Juventus have also been reprimanded after a separate UEFA investigation and as well as throwing the Italian giants out of European football, they have been fined €20 million.
However, half of that fine has been suspended and Juventus will only have to pay if their financial records for the next three years do not comply with the accounting requirements.
Juventus - who were docked 10 points last season over their past transfer dealings, effectively ending their hopes of Champions League qualification - were found to have violated the framework of a settlement agreement with UEFA in August last year.
Juventus president Gianluca Ferrero said in a statement on the club's website: "We regret the decision of the UEFA Club Financial Control Body.
"We do not share the interpretation that has been given of our defence and we remain firmly convinced of the legitimacy of our actions and the validity of our arguments.
"However, we have decided not to appeal this judgement. Despite this painful decision, we can now face the new season by focusing on the field and not on the courts."
