Tax Legal Services · Primary-source case analysis

United States v. Boyle: Reliance on Counsel Does Not Excuse a Known Filing Deadline

By Aneeta Mishra and Timothy Chan

Published May 3, 2026

United States v. Boyle draws a line between relying on professional substantive tax advice and delegating the nondelegable task of meeting a clear filing date.

The executor relied on the estate's attorney

The executor provided the necessary information and periodically asked about the estate-tax return. Counsel assured him it would be timely, but a clerical calendaring omission led to filing three months late and the IRS assessed a failure-to-file penalty.

The filing duty remained with the taxpayer

Hiring competent counsel may show ordinary business care in handling an estate, but it does not transfer the statutory duty to ensure a known return is filed on time. Determining and monitoring a fixed deadline requires no special tax expertise.

Agent error was not reasonable cause

The Court unanimously held that reliance on an agent to perform the ministerial act of timely filing did not constitute reasonable cause under section 6651(a)(1). The principal remained responsible even though counsel's failure might create a separate issue between client and lawyer.

Substantive legal advice is different

Boyle recognized a different problem when a taxpayer reasonably relies on professional advice about whether a return is legally required. The case concerned an admitted filing obligation and missed date, not erroneous expert advice on a genuinely technical substantive question.

Key takeaways

• Calendar the statutory deadline independently of the preparer.
• Confirm actual filing and retain acceptance evidence.
• Distinguish deadline delegation from reliance on substantive tax advice.
• Document any external event that made timely filing objectively impossible.