29 CFR § 99.230 - Audit costs.
(a) Allowable costs. Unless prohibited by law, the cost of audits made in accordance with the provisions of this part are allowable charges to Federal awards. The charges may be considered a direct cost or an allocated indirect cost, as determined in accordance with the provisions of applicable OMB cost principles circulars, the Federal Acquisition Regulation (FAR)(48 CFR parts 30 and 31), or other applicable cost principles or regulations.
(b) Unallowable costs. A non-Federal entity shall not charge the following to a Federal award:
(2) The cost of auditing a non-Federal entity which has Federal awards expended of less than $300,000 per year (or $500,000 for fiscal years ending after December 31, 2003) and is thereby exempted under § 99.200(d) from having an audit conducted under this part. However, this does not prohibit a pass-through entity from charging Federal awards for the cost of limited scope audits to monitor its subrecipients in accordance with § 99.400(d)(3), provided the subrecipient does not have a single audit. For purposes of this part, limited scope audits only include agreed-upon procedures engagements conducted in accordance with either the AICPA's generally accepted auditing standards or attestation standards, that are paid for and arranged by a pass-through entity and address only one or more of the following types of compliance requirements: activities allowed or unallowed; allowable costs/cost principles; eligibility; matching; level of effort; earmarking; and, reporting.