The probe follows the company’s fall into administration in December after lenders raised concerns about potentially suspicious transactions.

The FRC’s investigation will scrutinise the audits of the invoice-financing firm conducted between 2017 and 2023. Azets served as Stenn’s auditor until the 2023 financial year, when Big Four firm Deloitte took over.

Azets had originally been appointed after the previous auditor, EY, resigned in 2018. In a publicly filed letter, EY cited “concerns regarding certain related party transactions” and the “sufficiency of explanations” from management as reasons for its resignation.

The regulatory investigation focuses on two entities – Stenn Assets UK Limited and Stenn International Limited.

Stenn, once valued at $900 million (c. £663m) and partnered with major banks like Citigroup and Barclays, faced scrutiny after US authorities unsealed criminal indictments in a money laundering case. These documents made passing references to Stenn and its Russian founder, Greg Karpovsky. One indictment alleged that Stenn Assets UK had received $1.7m (c. £1.25) from a company linked to a Russian citizen who had pleaded guilty to running an unlicensed money transmitting business.

Spokespersons for both Deloitte and Azets have stated that they will cooperate fully with the FRC’s investigation.