09/02/2026
AI Hallucinated Tax Law Causing Major Problems For Entrepreneurs
A recent Tax Court case, Clinco, T.C. Memo. 2026-16, shows exactly what not to do when using Artificial Intelligence (AI). The decision provides a cautionary example for all entrepreneurs navigating the growing use of AI in accounting, tax, and legal research
The case involved the 2015 tax return of Peter L. Clinco, an attorney and entrepreneur who co-owned and operated MedCafe Westwood, a restaurant and bar near the University of California at Los Angeles.
The IRS audited the return and determined through a bank-deposit analysis that MedCafe’s gross receipts for the restaurant were underreported on Clinco’s Schedule C by more than $2.2M. Additionally, the court found Clinco was not entitled to $56,798 in depreciation deductions for two rental properties due to a lack of substantiation.
He challenged the IRS’s determinations in Tax Court, but the court upheld them. An unusual aspect of the opinion involved Judge Holmes' faulting Clinco’s attorney for submitting briefs citing nonexistent cases that the judge said appeared to have been hallucinated by generative AI.
Among other things, Clinco challenged the validity of a notice of deficiency because it lacked a manual “wet” signature. His attorney cited four cases supporting this argument, three of which the court described as likely large language model AI hallucinations.
The cases the court said appeared to be hallucinations were...
1 - Cacchillo, 130 T.C. 132 (2008): The taxpayer’s counsel claimed this case held that an improperly signed notice of deficiency ousted the court of jurisdiction. In reality, the case doesn't exist.
2 - Miller, 57 T.C. 440 (1971): This citation allegedly clarified formal signature requirements, but the case has no mention whatsoever of deficiency notices.
3 - Tefel, 118 T.C. 324 (2002): The court described this as nonexistent, noting that the cited page actually refers to Hillman, 118 T.C. 323 (2002), a case regarding S corporation management fees.
The court explicitly warned the attorney that submitting a brief filled with fictitious caselaw is a clear violation of Civil Procedures and is a "recipe for sanctions." Judge Holmes further stated that utilizing unchecked AI hallucinations in court is completely unacceptable.
The taxpayer ultimately lost the case on its merits. The Tax Court upheld the IRS's original assessment, holding the taxpayer liable for nearly $2.3 million in tax deficiencies stemming from unreported restaurant income and undocumented depreciation deductions.
Let me leave you with this...
Did I mention that this guy was an attorney? Of course they threw the book at him charging additional tax, interest and penalties.
This isn't an isolated case. There are several that I could have written about, but I used this one because it's such a blatant misuse of AI.
Do yourselves a favor. If you have an accounting or tax question, call a professional you trust and actually listen to their answer.
Don't google the question and then call the professional. Nothing rankles more than a client who wants to take my time to provide a professional answer and then questions it based on an AI answer.
Artificial Intelligence fails for many reasons, but the most common is that it doesn't actually speak our language. We have a specific nomenclature, unused by the outside world, that AI generally can't interpret.
A common difficulty is the use of the words "Self-Employed". In tax law that refers specifically to the law regarding a Sole Proprietor.
But how could generative AI know that this doesn't refer to the President of an S Corp or the Managing Member of an LLC who is also self-employed? Of course, AI gets it wrong.
Don't end up in hot water like Mr. Clinico, the attorney. If you have a question, please call.
And as always, if you're having difficulties with your accounting and tax work, I'm waiting to hear from you.
We're all going to get through this. Let's get through it together..
Accounting Solutions Ltd. stands ready to complete our mission and purpose of protecting you, your family, and your business. Whether you need Payroll Services, Accounting and Tax Work, Tax Planning, or Tax Representation, you have but to ask. I'm here and I remain,
Sincerely yours,
Chris Amundson
President
Accounting Solutions Ltd.
773-267-7500
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