The Big Picture: Why Sirius Solutions v. Commissioner Matters

Let’s cut to the chase: the U.S. Court of Appeals for the Fifth Circuit’s recent decision in Sirius Solutions, LLLP v. Commissioner is a game-changer for anyone who owns a piece of a limited partnership, especially if you’re in Texas, Louisiana, or Mississippi, but with ripple effects that could reach boardrooms and fund managers nationwide. If you’re a business owner, professional services partner, or private equity player, this is one of those rare tax cases that actually deserves your attention. The Fifth Circuit just told the IRS, in no uncertain terms, that when Congress said “limited partner” in the self-employment tax statute, they meant what they said. No more IRS “functional analysis” or “passive investor” mumbo jumbo. If you’re a limited partner under state law, with limited liability, you’re out of the self-employment tax—period, full stop.

But don’t pop the champagne just yet. The IRS isn’t going quietly, and the rest of the country is still playing by different rules. In Part 1, we’ll break down what happened in the case, the Fifth Circuit’s reasoning, and why the court sided with taxpayers over the IRS. Part 2 will cover what this means for you and what you should do about it.

The Facts: Sirius Solutions and the IRS Go to War

Sirius Solutions, LLLP is a Texas-based business consulting firm, organized as a Delaware limited liability limited partnership (LLLP). The firm’s ownership structure is classic: a general partner (Sirius Solutions GP, LLC) and a handful of individual limited partners. For the tax years 2014–2016, Sirius reported millions in ordinary business income, all allocated to its limited partners. Relying on the plain language of Section 1402(a)(13) of the Internal Revenue Code, Sirius excluded those distributive shares from self-employment tax, reporting zero net earnings from self-employment.

The IRS, never one to leave money on the table, audited Sirius and issued Notices of Final Partnership Administrative Adjustment (FPAA). The agency’s position? None of Sirius’s limited partners counted as “limited partners” for purposes of the self-employment tax exception. Why? Because they were too involved in the business—delivering services, supervising staff, negotiating client engagements, and generally acting like, well, business owners. The IRS said the law only protects “passive investors,” not folks who roll up their sleeves.

Sirius challenged the IRS in Tax Court. The Tax Court, citing its own recent precedent in Soroban Capital Partners LP v. Commissioner, sided with the IRS. The “limited partner” exception, the Tax Court said, only applies to partners who are truly passive. If you’re actively involved, you’re paying self-employment tax, no matter what your partnership agreement says.

Sirius appealed to the Fifth Circuit. And that’s where things got interesting.

The Fifth Circuit’s Opinion: Textualism Rides Again
“Limited Partner” Means…Limited Partner

The Fifth Circuit, in a majority opinion by Judge Oldham, took a hard look at the statutory language of Section 1402(a)(13). That section excludes from self-employment tax “the distributive share of any item of income or loss of a limited partner, as such, other than guaranteed payments…for services actually rendered.” The court’s question: What did Congress mean by “limited partner” when it wrote this law in 1977?

The answer, according to the appellate court, is refreshingly straightforward. Dictionaries and legal authorities from the 1970s defined “limited partner” as a partner in a limited partnership whose liability is limited to their investment. That’s it. The defining feature is limited liability—not whether the partner is passive or active, not how many hours they work, not whether they sit on committees or manage staff. The appellate court found that every contemporaneous dictionary agreed: “The touchstone of a ‘limited partner’ in 1977 was limited liability”.

Agency Guidance: IRS and SSA Agreed (Until They Didn’t)

The Fifth Circuit didn’t stop at dictionaries. It looked at how the IRS and the Social Security Administration (SSA) interpreted “limited partner” at the time. The IRS’s own instructions for Form 1065, dating back to 1978, defined a limited partner as “a partner in a partnership formed under a state limited partnership law, whose personal liability for partnership debts is limited to the amount of money or other property that the partner contributed or is required to contribute to the partnership.” The SSA’s regulations said the same thing: “You are a ‘limited partner’ if your financial liability for the obligations of the partnership is limited to the amount of your financial investment in the partnership”.

For over 40 years, the IRS told taxpayers that limited liability was the key. Only recently did the agency start pushing the “functional analysis” and “passive investor” theories. The appellate court was not impressed with this about-face, noting that “the lawbooks teem with examples of taxpayers who’ve learned the hard way what happens when they ignore IRS instructions”—so the IRS can’t just change the rules midstream.

Rejection of the “Functional Analysis” and Soroban Precedent

The Fifth Circuit took direct aim at the Tax Court’s “functional analysis” test, which asks whether a partner is really acting like a limited partner (i.e., passively) or more like a general partner (i.e., actively involved). The appellate court found this approach unworkable and inconsistent with the statute. Three main reasons:

Guaranteed Payments Clause: The statute taxes “guaranteed payments” for services rendered by limited partners. If limited partners were always passive, there’d be no need for this clause. Congress clearly contemplated that limited partners could perform services and still be limited partners for tax purposes.

Statutory Silence: Congress knows how to say “passive investor” or “passive income” when it wants to. It used those terms elsewhere in the tax code, but not here. The appellate court refused to read extra requirements into the statute.

“As Such” Language: The phrase “limited partner, as such” doesn’t mean “only when acting passively.” It’s a clarification for dual-status partners (those who are both general and limited partners), ensuring that only the limited partner portion of their income is excluded from self-employment tax.

The Fifth Circuit concluded that the IRS’s functional analysis “would require an army of lawyers and accountants—and a whole lot of luck” for taxpayers to figure out their tax liability. That’s not how tax law is supposed to work.

State Law vs. Federal Law: Substance Over Labels

The IRS argued that federal tax law shouldn’t turn on state-law labels. The Fifth Circuit agreed in principle but drew an important distinction: federal law determines what’s taxed, but state law creates the legal interests. So, to be a “limited partner” under Section 1402(a)(13), you must have the substantive rights of a limited partner—namely, limited liability—under state law. A state can’t just slap a “limited partner” label on a sole proprietor and get them out of self-employment tax. But if you have limited liability under a bona fide state-law limited partnership, you qualify.

Now to be clear, that is what State Law (at least Texas), intended historically, when they introduced Limited Partners. The limited liability, at least, anecdotally, was to come with a limited responsibility, but now the practice is looser. We often have LP’s and GP’s with near-zero participation in the business, because they let third parties handle operations. But the facts differ from partnership to partnership, so this is a moot point for the time being.

Application to Sirius: A Straightforward Win

Applying this rule to Sirius Solutions, the Fifth Circuit found the answer obvious. Sirius was a validly formed LLLP under Delaware law. Its limited partners had limited liability. The IRS’s attempt to apply a functional analysis to their activities was irrelevant. The appellate court vacated the Tax Court’s decision and sent the case back for further proceedings consistent with its opinion.

Judge Graves dissented, arguing that the majority’s interpretation opens a loophole that Congress never intended. He pointed to legislative history suggesting that Congress wanted to prevent business owners from avoiding Social Security taxes by calling themselves limited partners while still working full-time in the business. He also noted that the IRS’s own instructions use the word “generally” when describing the limited partner exception, implying that not all limited partners qualify. The dissent warned that the majority’s approach could undermine the Social Security system by letting active business owners escape self-employment tax.

What’s Next?

The Fifth Circuit has spoken clearly: limited partners with limited liability are exempt from self-employment tax on their distributive shares, regardless of how active they are in the business. But the battle is far from over. The IRS can appeal, other circuits are deciding similar cases, and the practical implications for taxpayers are significant.

In Part 2, we’ll explore what this decision means for limited partners, LLPs, LLCs, and professional services firms, and provide practical guidance on what you should do now.

Read Part II of this series →

This is for informational purposes only and does not constitute tax advice or a tax opinion.