Architecture Firm Entity Structure: LLC, S-Corp, or Partnership for Your Practice

Architecture firms get a significant advantage under the QBI deduction rules that many firm owners do not realize: architecture is explicitly not classified as a Specified Service Trade or Business (SSTB) under IRC 199A. Treasury Regulation 1.199A-5(b)(2)(vi) states that “services within the fields of architecture and engineering are not treated as consulting services,” which means architecture firms are treated the same as construction, manufacturing, and real estate businesses for QBI purposes, not the same as law firms, accounting firms, or medical practices.

This matters because non-SSTB businesses never lose the QBI deduction entirely. For firm owners with taxable income above $201,750 (single) or $403,500 (MFJ) for 2026, the deduction is limited to the greater of 50% of W-2 wages paid or 25% of W-2 wages plus 2.5% of the unadjusted basis of qualified property. That wage-based limitation makes the entity structure decision, and specifically the S-corp salary level, directly relevant to the QBI deduction calculation.

Why does the non-SSTB status matter for entity structure?

For a sole proprietor architect earning $200,000, the QBI deduction is approximately $40,000 (20% of $200,000), saving roughly $8,800 in federal income tax at the 22% bracket. Below the $403,500 threshold (MFJ), the deduction works the same regardless of entity type.

The entity structure becomes relevant for QBI above the threshold, because the W-2 wage limitation kicks in. A sole proprietor has no W-2 wages (Schedule C income is self-employment income, not wages), which means the QBI deduction for a sole proprietor above the threshold is limited to 2.5% of the unadjusted basis of qualified property, which for a service firm with minimal physical assets can be close to zero. An S-corp that pays $150,000 in W-2 salary creates a QBI deduction floor of $75,000 (50% of W-2 wages), saving up to $27,750 in federal tax at the 37% bracket, on top of the SE tax savings from the S-corp structure itself.

This dual benefit (SE tax savings plus a higher QBI deduction through the W-2 wage limitation) is why the S-corp election is particularly powerful for architecture firms earning above the threshold. A law firm or accounting firm at the same income level gets no QBI deduction at all because of its SSTB status; the architecture firm keeps it.

When does the S-Corp election make sense?

The S-Corp election is the most common structure for profitable single-owner architecture firms. It works by splitting income into two streams:

W-2 salary: Subject to payroll tax (employer and employee FICA, totaling 15.3% up to the wage base). The salary must be reasonable for the services performed.

Distributions: Not subject to payroll tax. The distribution is the remaining profit after salary and other expenses.

How are multi-owner architecture firms structured?

Most multi-owner firms are organized as partnerships (or multi-member LLCs taxed as partnerships). The partnership structure offers several advantages:

Flexible profit allocation: Partners can allocate income disproportionately to their ownership percentages, as long as the allocations have “substantial economic effect” under IRC 704(b). A senior partner who brings in 70% of the revenue can receive 70% of the profits even if ownership is split 50/50.

Multi-tier structures: A partnership can have different classes of partners (equity partners, income partners, junior partners) with different profit-sharing formulas. This allows the firm to reward producers and incentivize growth without changing the ownership structure.

Buy-in flexibility: New partners can buy in through capital contributions, promissory notes, or sweat equity arrangements. The partnership agreement governs the terms, and the tax treatment of the buy-in depends on whether the new partner acquires an interest in capital (which may trigger income recognition for the existing partners) or an interest in future profits only.

An S-Corp is less flexible for multi-owner firms because it allows only one class of stock. All shareholders receive distributions in proportion to their ownership, with no ability to allocate profits disproportionately. For firms with multiple partners at different levels, the partnership structure is almost always preferable.

What are the state-level requirements?

Most states require architecture firms to organize as Professional LLCs (PLLCs), Professional Corporations (PCs), or Professional Limited Liability Partnerships (PLLPs). The specific requirements vary by state, but common features include:

• All owners must be licensed architects (or licensed in a related profession, depending on the state)
• The firm must register with the state board of architecture
• The entity name must include a professional designation (PLLC, PC, etc.)
• The firm’s professional liability is not eliminated by the entity structure (the licensed professionals remain personally liable for their own professional acts, though the entity shields owners from the malpractice of other owners)

The federal tax treatment is independent of the state organizational form. A PLLC taxed as a partnership files Form 1065. A PC can elect S-Corp status. The state-level requirements affect entity formation and liability, not federal tax classification.

How do partner buy-ins work?

When a new partner joins an architecture firm, the buy-in transaction has tax consequences that depend on the structure:

Capital interest purchase: The new partner pays the existing partners for a share of the firm’s assets (including goodwill). The existing partners recognize gain or loss on the sale. The new partner’s basis in the partnership interest is the purchase price. If the partnership makes a Section 754 election, the new partner gets a step-up in the inside basis of the partnership’s assets, which increases future depreciation and amortization deductions.

Profits interest: The new partner receives an interest in future profits only, without paying for existing capital. Under Revenue Procedure 93-27, a profits interest granted for services is generally not a taxable event at the time of grant (if certain conditions are met). The new partner begins receiving allocations of future income, and the value builds over time.

Sweat equity with vesting: The new partner receives an ownership interest that vests over time (3-5 years). This can be structured as a profits interest (tax-free at grant) or a capital interest with an IRC 83(b) election (tax paid at grant on the current value, which may be low).

Related guides:

• Architecture Firm Multistate Nexus Licensing
• Architecture Firm Professional Liability Insurance Tax
• Architecture Firm Project Accounting Revenue Recognition
• Architecture Firm Retirement Plans Partner
• Architecture Firm Succession Ownership Transition

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.