Chelsea have been charged by the Football Association with 74 alleged rule breaches related to payments to agents between 2009 and 2022.
The charges are primarily focused on transfers between the 2010-11 and 2015-16 seasons.
Three deals that form part of the investigation involved Eden Hazard, Samuel Eto'o and Willian.
There is no suggestion of any wrongdoing on the part of those players.
Russian oligarch Roman Abramovich was in control of the club from 2003 to 2022, before selling Chelsea to a consortium led by American investor Todd Boehly and private equity firm Clearlake Capital.
The alleged rule breaches concern agents, intermediaries and third-party investments in players.
Chelsea, who said they had reported the potential rule breaches to the FA themselves, have until 19 September to respond.
There are a wide range of options available to sanction Chelsea, including a fine, transfer embargo and points deduction. However, the Blues' high level of co-operation will be factored in and the club don't expect to be hit with a sporting sanction.
Sources at Chelsea also say they have no concerns about the impact of any future fines on compliance with the Premier League's profit and sustainability regulations (PSR) having factored in a potential punishment after the takeover of the club in 2022.