Canada-based accounting firm Smythe agreed to pay a $175,000 penalty in settling with the Public Company Accounting Oversight Board (PCAOB) regarding its use of unregistered firms across four issuer audits.

Smythe overrelied on the work of PKF Audisur and PwC Malta in violation of PCAOB rules, the agency said in a press release Tuesday. The PCAOB required Smythe to review and evaluate its quality control policies and procedures, among its remedial mandates.