This marks the third instance this year that the Big Four firm has been targeted regarding potentially unauthorised auditors signing off on accounts.

The FRC’s inquiry focuses on a breach of “partner rotation” rules – strict regulations designed to maintain auditor independence by limiting how long a specific partner can lead a client’s audit.

The Big Four firm, which has audited Shell for nearly a decade and was paid $66 million (c. £50m) for its 2024 work, admitted to breaching rotation rules and has pledged full co-operation with the regulator.

Shell disclosed the non-compliance in July 2025. The company immediately refiled its Form 20-Fs for 2023 and 2024 but emphasised that its financial statements remain unchanged and EY’s audit opinions remain unqualified.

The FRC’s decision to open the investigation was made at a meeting of the FRC’s Conduct Committee on 21 October 2025. The investigation will be conducted by the FRC’s enforcement division under the audit enforcement procedure.