Clients are untrustworthy.  As a tax controversy attorney, this is my experience. I have heard that other types of law deals with more honorable sorts, but I'll believe it when I see it.  When a client comes to you and says "whoopsie, I forgot to report [insert absurdly large number here] on my return, what should I do?" what should you tell him?  What if the IRS has already discovered the understatement?  Is he under the obligation to file an amended return?  Are you required to tell him to file one? In this brief article, Briefly Taxing examines amended returns in general, whether filing them is required, and whether a CPA and tax attorney must advise their client to file an amended return. Quick Rules An amended return filed by a taxpayer reporting an underpayment is an admission by that taxpayer of an underpaid tax liability.[1] The taxpayer has no…