Most law firms settle on a tax structure at formation and, understandably, don't give it much thought afterward. There's usually no obvious reason to: the firm files its returns, partners get paid, and the structure fades into the background.
But the S-corp vs. partnership decision touches nearly everything in accounting for lawyers: how much self-employment tax you pay, whether you can claim the Qualified Business Income (QBI) deduction, how state taxes flow through to your personal return, and how flexibly you can split profits among partners. As firms grow and tax laws change, a structure that made sense at formation may no longer be the best fit. The right answer depends on your firm's size, income level, and state — and it's worth understanding the trade-offs before deciding whether a change is warranted.
The Legal Entity and the Tax Classification Are Separate Questions
First, a clarification that trips up many firm owners: "S-corp vs. partnership" isn't really a choice between two legal entities. Most law firms operate as PLLCs, LLPs, or professional corporations — whatever their state bar rules permit — and the tax classification sits on top of that. A PLLC with multiple members is taxed as a partnership by default, but it can elect S-corp taxation by filing Form 2553 with the IRS.
Both classifications are pass-throughs: the firm itself generally pays no federal income tax, and profits flow through to the owners' personal returns. The differences show up in how that income is characterized once it gets there.
Self-Employment Tax: Where the S-Corp's Advantage Shrinks
The S-corp's headline benefit is well known. Shareholder-employees split their income between a W-2 salary (subject to payroll taxes) and distributions (which generally are not). Partners in a partnership, by contrast, typically pay self-employment tax on their full distributive share of firm income.
For many businesses, that split creates real savings. For law firms, the math compresses. The IRS requires S-corp owners to pay themselves "reasonable compensation" before taking distributions — and for an attorney whose income is generated almost entirely by personal services, the defensible salary is a large share of what the firm earns per partner. An aggressive low-salary position invites IRS scrutiny, and payroll tax cases are ones the IRS tends to win.
The savings aren't zero, particularly for firms with associates and staff generating leverage beyond the owners' own billable work. But they're rarely as dramatic as generic entity-choice advice suggests.
Key Takeaway: The S-corp payroll tax arbitrage that works well for product businesses compresses significantly for law firms, because a lawyer's reasonable compensation is most of what the firm earns per partner. Run the actual numbers before restructuring around this benefit alone.
The QBI Deduction and the SSTB Problem
The QBI deduction — now a permanent feature of the tax code — allows eligible pass-through owners to deduct up to 20% of qualified business income. The catch for attorneys: law is a "specified service trade or business" (SSTB), so the deduction phases out entirely once taxable income exceeds certain thresholds (roughly $203,000 for single filers and $406,000 for joint filers in 2026, indexed annually).
Below those thresholds, structure affects the calculation. S-corp W-2 wages paid to the owner don't count as QBI, and neither do partnership guaranteed payments — so how you pay yourself directly changes the deduction's size. Above the thresholds, QBI is generally off the table for attorneys regardless of structure, which simplifies the analysis but removes a benefit other business owners enjoy.
State Taxes and the PTET Election
For successful partners in high-tax states, the pass-through entity tax (PTET) election often matters more than the S-corp vs. partnership question itself. Both structures can generally elect into state PTET regimes, including New York's, which allow the firm to pay state income tax at the entity level and deduct it as a business expense — bypassing the federal cap on state and local tax (SALT) deductions.
That cap currently sits at $40,000 through 2029, but it phases back down toward $10,000 for taxpayers above roughly $500,000 of income. In other words, the more successful the partner, the more the PTET election is worth – to a point. The catch is timing: New York's election is generally due March 15 for the year in question, and missing it means waiting until next year. Firms operating in New York City also need to account for the Unincorporated Business Tax, which applies to partnerships but not S-corps — a genuine point in the S-corp's favor for city-based practices.
Key Takeaway: The PTET election is a use-it-or-lose-it annual deadline, and for high-earning partners it frequently delivers more tax savings than entity choice does. If your firm hasn't evaluated it, that analysis should come before any restructuring conversation.
Compensation Flexibility Often Decides It
Here's the factor that settles the question for most multi-partner firms: S-corps must distribute profits strictly pro-rata by ownership percentage. Partnerships can make special allocations — compensating partners based on originations, billable hours, or whatever formula the partnership agreement specifies.
For a firm where partners contribute unequally, the S-corp's rigidity is usually a dealbreaker. The payroll tax savings rarely justify losing the ability to tie compensation to performance. This is also why unequal profit splits show up in the profitability metrics managing partners track: partnership taxation lets your economics follow your actual firm dynamics. Retirement plan contributions and bookkeeping mechanics also differ between the two structures, so a change ripples through more of your operations than the tax return alone.
Key Takeaway: Solo and small firms below the QBI thresholds are typically the strongest S-corp candidates. Multi-partner firms with performance-based compensation almost always belong in partnership taxation — and NYC's UBT is the main exception worth modeling.
Getting the Structure Right for Your Firm
There's no universal answer here, and that's precisely the point: this decision is a modeling exercise, not a rule of thumb. The variables — reasonable compensation, QBI eligibility, PTET savings, UBT exposure, and partner compensation dynamics — interact differently at every income level and in every state.
At Revonary, our accounting services for law firms include exactly this analysis. We model your firm's numbers under each structure, flag the elections and deadlines that apply to you, and make sure the structure you chose years ago still fits the firm you run today. Contact us to start the conversation before the next election deadline passes.
