The Financial Conduct Authority has launched a fresh probe into the misconduct of the Halifax Bank of Scotland (HBOS) assets team in Reading between 2003 and 2010.
Six of the team have been jailed, with five being found guilty of corruption, fraudulent trading and money-laundering offences.
The regulator put its investigation on hold in 2013 at the request of Thames Valley Police.
But now it will focus on whether those inside HBOS knew of the offences taking place.
It will also scrutinise HBOS’s communications with former regulator the Financial Services Authority after the misconduct was discovered.
In a statement the FCA wrote: “This resumes an FCA investigation that was placed on hold in early 2013 at the request of Thames Valley Police pending the outcome of the Thames Valley police investigation and any resulting prosecutions.
“The FCA’s investigation is focussing on the extent and nature of the knowledge of these matters within HBOS and its communications with the Financial Services Authority after the initial discovery of the misconduct.”
The jailed managers included Lyden Scourfield, who accepting bribes from consultant David Mills in the form of sex parties, designer watches and holidays between 2003 and 2007.
In return Scourfield told customers to use Mills’ firm, Quayside Corporate Services, which made inappropriate loans to struggling businesses and charged companies high consultancy fees for the service.