Construction Company Entity Structure: LLC, S-Corp, and the QBI Deduction for Contractors

Most contractors start as sole proprietors, form an LLC when someone tells them they need one, and eventually hear that an S-corp election will save them on taxes. All three of those steps are usually correct, but the timing, the salary they set, and the way they structure equipment ownership determine whether the S-corp actually saves money or just creates more paperwork. Construction companies sit in a particularly favorable position for the IRC 199A qualified business income (QBI) deduction because construction is not a specified service trade or business, which means the 20% deduction is available at every income level. The catch is that the deduction has a W-2 wage limitation that interacts directly with the reasonable salary the S-corp shareholder pays themselves, and getting that balance wrong means leaving money on the table in one direction or the other.

Why do most contractors start as a sole proprietorship and should they stay there?

A sole proprietorship is where most contractors begin because there is nothing to file. You get a contractor’s license, open a bank account, and start bidding jobs. There’s no formation document, no annual report, and no separate tax return. The income goes on Schedule C of your personal Form 1040, and you’re done.

The problem is that every dollar of net income from a sole proprietorship is subject to self-employment tax under IRC 1401. For 2025, that means 12.4% for Social Security on the first $168,600 of net self-employment earnings, 2.9% for Medicare on all earnings, and an additional 0.9% Medicare tax on earnings above $200,000 ($250,000 if married filing jointly). On $200,000 of net profit, the self-employment tax alone is roughly $28,000. That tax exists regardless of whether the contractor takes the money out of the business or leaves it in the bank account to cover payroll and materials for the next job.

A single-member LLC taxed as a disregarded entity does not change this calculation at all. The LLC provides liability protection (separating business debts from personal assets), but for federal income tax purposes it is invisible. The IRS treats it identically to a sole proprietorship, and the self-employment tax is the same dollar for dollar. The LLC is still worth forming for the liability shield, especially in construction where jobsite injuries, property damage claims, and contract disputes are routine. But it is not a tax play on its own.

The entity that changes the tax math is the S-corp election.

How does the S-corp election reduce a contractor’s self-employment tax?

An S-corp is not a separate type of entity. It is a tax election, filed on Form 2553, that changes how the IRS taxes an existing LLC or corporation. Under IRC 1363(a), an S corporation is generally not subject to federal income tax at the entity level. Instead, the income passes through to the shareholders and is taxed on their personal returns.

The self-employment tax savings come from splitting the income into two buckets. The contractor pays themselves a W-2 salary through the S-corp’s payroll, and that salary is subject to FICA taxes (the employer and employee shares of Social Security and Medicare). The remaining profit is distributed to the shareholder as a distribution that is not subject to FICA. The FICA savings come from the gap between total net income and the salary.

The election must be filed by March 15 of the first year the S-corp status is to take effect. For a new entity, it must be filed within 75 days of formation. Missing the deadline does not mean waiting until next year in every case: the IRS grants late election relief under Rev. Proc. 2013-30 when reasonable cause exists and the entity has been filing consistently with S-corp treatment. But “I didn’t know about the deadline” is tested case by case, and relief is not guaranteed.

What counts as reasonable compensation for a contractor?

The salary the S-corp shareholder pays themselves must be “reasonable compensation” for the services they perform. This is not optional. The IRS has won multiple cases where S-corp shareholders paid themselves minimal salaries (or no salary at all) and took the rest as distributions to avoid FICA. The consequence of getting caught is reclassification of distributions as wages, with back FICA taxes, penalties, and interest assessed on the entire reclassified amount.

For a construction company owner, reasonable compensation is what you would pay someone to do your job if you weren’t the owner. The IRS looks at several factors:

• The duties performed (estimating, project management, jobsite supervision, client relations, equipment operation, bookkeeping, business development)
• Training and experience (a master electrician with 20 years of experience commands more than a new GC)
• Comparable pay in the geographic market (Bureau of Labor Statistics data, construction industry salary surveys, local hiring posts for similar roles)
• The company’s revenue and size
• Hours worked

A hands-on general contractor running a $2M-$5M revenue operation, managing projects, handling estimating, and supervising crews typically falls in the $80,000-$130,000 range depending on the market. A specialty subcontractor (plumber, electrician, HVAC) running a $1M-$2M operation would typically be in the $70,000-$110,000 range. These are ballpark figures, and the defensible salary for any specific contractor depends on the actual facts.

The practical risk: setting the salary below $40,000-$50,000 for a full-time owner-operator is almost always indefensible, and setting it below the median wage for a comparable position in the same metro area is asking for trouble. Keep the documentation (salary surveys, job descriptions, comparable job postings) in your corporate records. If the IRS challenges the salary, the documentation is the defense.

How does the QBI deduction work for construction companies?

The qualified business income deduction under IRC 199A allows owners of pass-through businesses (S-corps, partnerships, sole proprietorships) to deduct up to 20% of their qualified business income from their taxable income. For a contractor with $300,000 in QBI, that is a potential $60,000 deduction, which at a 32% marginal tax rate saves $19,200 in federal income tax.

Construction companies have a structural advantage here. The deduction is limited or eliminated for specified service trades or businesses (SSTBs), which include fields like law, accounting, health, consulting, athletics, financial services, and “any trade or business where the principal asset of such trade or business is the reputation or skill of 1 or more of its employees or owners” under IRC 199A(d)(2). Construction is not on that list. A general contractor, a plumber, an electrician, a roofer, a concrete company, and a heavy civil contractor all qualify for the QBI deduction at every income level.

This matters because for SSTBs, the deduction phases out entirely once taxable income exceeds $241,950 (single) or $483,900 (MFJ) for 2025. A law firm partner making $500,000 gets zero QBI deduction. A general contractor making $500,000 still qualifies, subject only to the W-2 wage and UBIA limitations described below.

What is the W-2 wage limitation and how does it interact with the S-corp salary?

For taxpayers with taxable income below $191,950 (single) or $383,900 (MFJ) for 2025, the QBI deduction is simply 20% of QBI with no further limitation. Above those thresholds, the deduction is limited to the greater of:

(a) 50% of the W-2 wages paid by the business, or

(b) 25% of W-2 wages paid by the business, plus 2.5% of the unadjusted basis immediately after acquisition (UBIA) of qualified property held by the business at the close of the tax year.

This is where entity structure and salary decisions collide. The S-corp shareholder’s own W-2 salary is the primary source of “W-2 wages” for this calculation. Wages paid to employees (crew members, office staff, project managers) also count. A contractor with a large payroll has plenty of W-2 wages to support the QBI deduction even with a modest owner salary. A contractor who subs out most of the work and has a small payroll may find that the QBI deduction is limited by insufficient W-2 wages.

The UBIA alternative (option b) is particularly valuable for construction companies that own heavy equipment. UBIA is the original cost of the property (not reduced for depreciation), measured at the date the property was placed in service, and it counts for the QBI limitation as long as the property is still within its MACRS recovery period or ten years from the placed-in-service date, whichever is later. A contractor who bought a $400,000 excavator five years ago and has fully depreciated it under Section 179 or bonus depreciation still has $400,000 of UBIA for the QBI calculation, even though the tax basis is zero. This means the equipment’s contribution to the QBI deduction continues for years after the depreciation deduction is taken.

Should a contractor use a multi-entity structure?

Many established contractors operate with two entities: an operating company (typically an S-corp) that bids jobs, employs crews, and carries the contractor’s license, and an equipment holding company (typically an LLC taxed as a disregarded entity or a partnership) that owns the heavy equipment, vehicles, and sometimes real property. The operating company leases the equipment from the holding company at fair market value.

The reasons for this structure are practical, not theoretical.

Asset protection. Construction carries significant liability exposure: jobsite injuries, property damage, defective work claims, contract disputes, and environmental claims. If the operating company faces a judgment that exceeds its insurance coverage, the equipment in a separate entity is shielded from the operating company’s creditors (assuming the entities are properly maintained with separate bank accounts, separate books, and arm’s-length lease terms). Without the separation, a single large claim can reach everything the contractor owns inside the business, including the equipment fleet that produces the revenue.

Surety bonding. The surety underwrites the contractor’s capacity to complete bonded work, and the operating entity’s balance sheet is the primary underwriting target. The surety evaluates working capital (current assets minus current liabilities), net worth, and the ratio of backlog to working capital. Equipment in a separate entity is still available for the surety’s analysis (the indemnity agreement typically covers all entities and the personal assets of the principal), but it sits outside the operating company’s direct claims exposure. This can improve the operating company’s financial profile for bonding purposes by keeping the balance sheet cleaner, especially when the equipment carries debt. For more on how the surety evaluates these numbers, see construction insurance, bonding, and surety tax treatment.

Depreciation and Section 179 flexibility. The equipment holding company’s depreciation and Section 179 elections can be planned independently of the operating company’s income. If the operating company is an S-corp and the equipment entity is a disregarded LLC, the depreciation still flows through to the owner’s personal return, so the net tax result is the same. But if the equipment entity is a partnership (because a partner or investor co-owns the equipment), the depreciation allocations follow the partnership agreement, which provides flexibility that a single S-corp cannot replicate.

Sale flexibility. If the contractor sells the operating business, the equipment entity stays. The buyer gets the contracts, the license, the workforce, and the brand. The seller keeps the equipment and leases it to the buyer (or to a new operation), creating a stream of rental income that continues after the sale. This can significantly affect the sale price and the tax treatment of the gain.

The costs of the multi-entity structure: two sets of books, two tax returns, a written equipment lease at arm’s-length rates, separate bank accounts, and the discipline to keep the entities genuinely separate. For a contractor running under $1M in revenue with minimal equipment, the cost usually exceeds the benefit. For a contractor with a seven-figure equipment fleet and bonded work, the structure pays for itself.

Is there a case for a C-corp in construction?

Rarely, and only for specific fact patterns. A C corporation pays federal income tax at a flat 21% rate under IRC 11(b), compared to the top individual rate of 37%. That lower rate sounds attractive until the second layer hits: distributions from the C-corp to the shareholder are taxable as dividends under IRC 301(c)(1), at either the qualified dividend rate (0%, 15%, or 20% depending on the shareholder’s income) or ordinary rates for non-qualified dividends. The combined effective rate on distributed profits (21% corporate plus 23.8% on qualified dividends at the top rate, including the 3.8% net investment income tax) reaches approximately 39.8%, which exceeds the top individual rate available through a pass-through entity with the QBI deduction.

The C-corp becomes worth modeling when the company retains significant profits for growth rather than distributing them. A large general contractor reinvesting profits into equipment, bonding capacity, and working capital may pay less tax in a C-corp while the money stays inside the entity. The 21% corporate rate on retained earnings is lower than what the same income would cost the owner at the top individual rate (37% less the 20% QBI deduction). But any time the money comes out, the second layer applies, and the lifetime tax cost typically exceeds the pass-through alternative.

For most contractors, the C-corp is not the right answer. The QBI deduction, the FICA savings from the S-corp election, and the flexibility of pass-through treatment make the S-corp (or S-corp plus equipment LLC) the default winner. A C-corp analysis makes sense only for firms with consistent annual net income well above $500,000 that plan to retain most of their earnings for several years.

Do state taxes change the S-corp calculation?

They can change it enough to shift the answer. Several states impose entity-level taxes on S-corps that do not apply to sole proprietorships or disregarded LLCs:

• California imposes a 1.5% net income tax on S-corps (minimum $800/year), plus the $800 annual LLC fee if the entity is an LLC that elected S-corp status.
• Illinois imposes a 1.5% replacement tax on S-corp income.
• New York City taxes S-corps at the corporate rate (8.85%).
• Tennessee historically imposed the Hall tax on S-corp distributions (repealed as of 2021, but still relevant for older returns under examination).

These state-level taxes reduce the net savings from the S-corp election and must be factored into the break-even analysis. A contractor netting $100,000 in California saves roughly $10,000 in FICA through the S-corp election but pays $1,500 in state S-corp tax plus the $800 annual fee, reducing the net benefit to roughly $7,700 before the additional compliance costs.

On the other side of the ledger, the pass-through entity tax (PTET) election that most states now offer can create a significant benefit for S-corp owners in high-tax states. The PTET allows the S-corp to pay state income tax at the entity level, and that payment is deductible by the entity for federal purposes, effectively bypassing the $10,000 SALT deduction cap on the owner’s personal return. For a contractor in a state with a 5-9% income tax rate, the PTET election can save thousands of dollars that would otherwise be lost to the SALT cap. Whether the PTET is available, and how it interacts with the state’s own S-corp tax, varies by state and changes frequently.

What are the most common mistakes contractors make with entity structure?

Five mistakes appear repeatedly in the files of contractors who come in for a review.

Setting the S-corp salary too low. The contractor nets $300,000, pays themselves a $40,000 salary, and takes $260,000 in distributions. The IRS reclassifies a substantial portion of those distributions as wages, assesses FICA on the reclassified amount, adds penalties for failure to deposit payroll taxes, and charges interest from the original due date. The cost of the reclassification almost always exceeds what the contractor would have paid in FICA at a reasonable salary.

Missing the Form 2553 deadline. The S-corp election for an existing entity must be filed by March 15 of the first year it is to take effect. A contractor who decides in October to be an S-corp “this year” has missed the window for the current year. Late election relief exists but is not guaranteed and costs time and professional fees to obtain.

Failing to maintain corporate formalities. The S-corp must operate as a separate entity: its own bank account, its own payroll (with W-2s, quarterly payroll tax deposits, and annual Form 940/941 filings), its own books, and documented shareholder actions. A contractor who runs the S-corp’s income and expenses through a personal bank account, does not run payroll, and has no corporate records is inviting the IRS (or a state agency, or a plaintiff in a lawsuit) to ignore the entity altogether.

Ignoring the QBI wage limitation. A contractor above the income threshold who uses mostly subcontractors and has minimal W-2 wages may lose most or all of the QBI deduction. The fix is not necessarily to hire more employees. It may be to set the owner’s salary high enough to support the deduction, or to restructure the sub relationships as employer-employee relationships where the facts support it (though worker classification has its own set of rules and risks).

Not separating equipment from the operating entity. A contractor who owns $800,000 in equipment inside the same entity that carries the contract liability is one bad jobsite accident away from losing the equipment to a judgment. The multi-entity structure is not complicated to set up and costs relatively little to maintain. The cost of not having it is measured in what happens when things go wrong.

What should I do next?

If you’re operating as a sole proprietor or single-member LLC and your net income consistently exceeds $60,000-$80,000, the S-corp election analysis is the first step. If you already have the S-corp but have not documented your reasonable compensation, build the comparability file now. If your taxable income is above the QBI threshold, run the W-2 wage limitation calculation to confirm you’re not leaving deduction on the table.

The entity structure decision does not exist in isolation. It connects to how you handle equipment depreciation, how you account for work in progress and contractor deductions, how your surety evaluates your balance sheet, whether your workers are properly classified, and whether your job costing supports the financial statements the entity needs to produce. If you work across state lines, the multi-state tax guide for contractors covers the nexus, withholding, and sales tax obligations that follow the entity into every state where you take a job. The restaurant entity structure guide covers the same S-corp and multi-entity analysis for a different industry if you want a side-by-side comparison. The trucking entity structure guide covers it for owner-operators, where the QBI deduction’s UBIA advantage from the truck itself and the DOT operating authority transition are the industry-specific factors.

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