Nottingham Forest owner Evangelos Marinakis is facing scrutiny from the Premier League after promotion.
The Greek shipping magnate was passed fit to own a club by the EFL before completing his £50million purchase of Forest five years ago, despite being the subject of multiple investigations into alleged match-fixing and drug trafficking.
But the Premier League are making their test more stringent as they seek to head off the threat of an independent regulator.
Marinakis has been charged with several serious offences in Greece before being cleared.
In 2019 the Olympiakos owner was charged with match-fixing and involvement in criminal gangs before being acquitted by the Court of Appeal two years later, and last year a Greek judge ruled there was no evidence after he was charged with heroin smuggling.