AICPA Code of Professional Conduct A02-17x

Provide circumstances where tax-related contingent fees are permitted.

Any of these circumstances:

• For work influencing legislation and statute, and obtaining a private letter ruling.
• For client representation during an IRS examination.
• For an amended return leading to a refund subject to examination by a tax authority.
• For an amended return leading to a refund involving a test case tax matter.