5th Cir.

Montero v. Commissioner of Internal Revenue

June 10, 2026 ·26-60167 ·Per Curiam · By Maria Santos

The United States Court of Appeals for the Fifth Circuit affirmed a Tax Court decision upholding a frivolous-filing penalty and a twenty-five thousand dollar sanction against a pro se taxpayer. The court rejected the petitioner's repeated arguments that his salary is not taxable income, citing his extensive history of advancing groundless positions.

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Background

Pro se Petitioner Aldofo Sandor Montero appealed a Tax Court decision that upheld the Internal Revenue Service Independent Office of Appeals’ imposition of a frivolous-filing penalty for the taxable year 2020. The Tax Court also imposed a twenty-five thousand dollar sanction for advancing a frivolous position.

The court’s reasoning

The court noted that Montero is no stranger to making frivolous arguments to avoid paying income tax. It cited multiple prior decisions where the Fifth Circuit rejected his assertion that his salary from Dell is not taxable income. The court found that the Tax Court did not abuse its discretion in issuing a sanction, noting that Montero had been repeatedly warned of the risk of advancing frivolous arguments yet continued to do so. The court concluded that imposing the maximum sanction was not an abuse of discretion given Montero’s extensive history.

Adolfo Montero is no stranger to making frivolous arguments to avoid paying income tax.

Montero v. Comm’r of Internal Revenue, No. 24-60190, 2024 WL 4491604, *1 (5th Cir. Oct. 15, 2024)

What it means going forward

The decision reinforces the Fifth Circuit’s stance against taxpayers who repeatedly advance frivolous arguments regarding the taxability of income, confirming that courts may impose maximum sanctions for such conduct.