The primary sources of AICPA audit standards and guidance regarding single audits are Statement on Auditing Standards (SAS) No. 74, Compliance Auditing Considerations in Audits of Governmental Entities and Recipients of Governmental Financial Assistance (AICPA, Professional Standards, vol. 1, AU sec. 801), and the AICPA Audit Guide Government Auditing Standards and Circular A-133 Audits (the Guide). In addition to guidance on performing audits under Government Auditing Standards, the Guide provides guidance on the auditor's responsibilities when conducting a single audit or program-specific audit in accordance with the Single Audit Act and Circular A-133.
Circular A-133 provides for the issuance of a compliance supplement to assist auditors in planning and performing the required audits. Office of Management and Budget (OMB) Circular A-133, Compliance Supplement (the Supplement) identifies important compliance requirements that the federal government expects to be considered as part of an audit in accordance with the Single Audit Act and Circular A-133. Use of the Supplement is mandatory.
The Supplement is updated annually and contains specific audit guidance relating to individual federal programs. The Supplement provides a source of information for auditors to understand federal program objectives, procedures, and compliance requirements, as well as audit objectives and suggested audit procedures for determining compliance with these requirements.