Mayo Foundation for Medical Education & Research v. United States
The Court upheld a Treasury Department rule that medical residents who work 40 or more hours a week are not tax-exempt 'students,' even though they are also being trained in their specialty.
The ruling also settled a broader administrative-law question: courts must review IRS and Treasury regulations under the same deferential Chevron framework used for other federal agencies, rather than a special, less deferential test just for tax rules.
“We do not doubt that Mayo’s residents are engaged in a valuable educational pursuit or that they are students of their craft.”
The Court acknowledges residents' educational role while still upholding the tax rule against them.
How it got here: Mayo sued for a tax refund; the district court struck down the rule, but the Eighth Circuit reversed and upheld it, prompting Mayo's appeal to the Supreme Court.
The Case in Depth
What happened
The Mayo Clinic and the University of Minnesota run medical residency programs where new doctors spend 50 to 80 hours a week treating patients while also attending lectures and exams, earning stipends and benefits. A federal tax law exempts students working for their schools from Social Security taxes, but a 2004 Treasury Department rule said anyone scheduled to work 40 or more hours a week for the school could never count as such a student, regardless of any educational component to the job.
The question before the Court
Are full-time medical residents "students" exempt from Social Security payroll taxes, or can the Treasury Department treat anyone working 40+ hours a week as a taxable employee?
Why it matters
Medical residents nationwide, along with their teaching hospitals, must keep paying and withholding Social Security and Medicare taxes on residents' stipends, preserving future disability and survivor benefits for those doctors. More broadly, the decision means taxpayers challenging any IRS or Treasury regulation can no longer argue for a friendlier legal standard than applies to other federal agencies' rules.
What changes now
The ruling is final on the merits; Mayo's residents remain subject to FICA taxes going forward, and the roughly 7,000 similar refund claims filed by other institutions after an earlier appeals court ruling are resolved by this decision's logic. The broader administrative-law holding — that tax regulations get the same Chevron deference as other agencies' rules — governs how future challenges to IRS and Treasury regulations will be litigated.
What this does not decide
The Court did not decide whether medical residents are "students" in any everyday sense — it said they may well be engaged in valuable educational training. It decided only the narrower legal question of how much deference courts owe the Treasury Department's line-drawing for FICA tax purposes.
How the Court got there
The legal reasoning, step by step
- The Court first asked, under the initial step of the two-part Chevron framework, whether Congress had directly spoken to the precise question of whether medical residents count as 'students.' It found the statute silent — it never defines 'student' or singles out residents.
- The Court then had to pick which legal test governs when a Treasury Department tax regulation is ambiguous: a more searching multi-factor test from a prior tax case (National Muffler) that scrutinizes a rule's age, consistency, and history, or the ordinary Chevron/Mead framework used for other federal agencies, which simply asks whether the agency's reading is reasonable.
- The Court held there is no basis for giving tax regulations less deference than other agencies' rules, reasoning that administering the tax code requires the same kind of complex interpretive judgment Congress expects agencies to exercise when filling gaps in any statute.
- Because the Treasury Department issued the rule under an explicit general grant of rulemaking authority and used full notice-and-comment procedures — both features the Court has previously treated as strong signs that Congress meant a rule to carry the force of law — the ordinary Chevron/Mead framework, not the older tax-specific test, applied here.
- Applying Chevron's second step, the Court found the 40-hour rule reasonable because it sensibly separates full-time workers from students by looking at hours worked, avoids costly case-by-case litigation over each employee's motives, and lines up with the Social Security Administration's view that residents should keep earning disability and survivor benefits.
Doctrinal impact
Cases affected by this decision
Limits National Muffler Dealers Assn., Inc. v. United States (440 U. S. 472)
Its special multi-factor test for reviewing tax regulations no longer applies; ordinary Chevron deference governs instead.
Abrogates Rowan Cos. v. United States (452 U. S. 247)
Its rule of reduced deference for regulations issued under general rulemaking authority no longer controls.