Tax Strategy for Engineering and Architecture Firms (2026)

Engineering and architecture firms hold a specific advantage in the qualified business income rules that most professional service firms do not. Both fields were carved out of the specified service trade or business definition, which means the 20% deduction remains available at any income level.

That single fact is worth six figures annually to a mid-sized firm, and it changes how salary and entity decisions should be made.

Engineering and Architecture Are Not SSTBs

IRC Sec. 199A(d)(2)(A) defines a specified service trade or business by reference to IRC Sec. 1202(e)(3)(A), but expressly excludes engineering and architecture from that reference.

The result is that an engineering or architecture firm may claim the full qualified business income deduction even at high income, subject only to the W-2 wage and qualified property limitations rather than the SSTB phase-out.

On $1,400,000 of qualified business income, that is a $280,000 deduction that a law firm or medical practice at the same income cannot claim.

Note the asymmetry with Sec. 1202. Engineering and architecture remain excluded businesses for qualified small business stock purposes under IRC Sec. 1202(e)(3), so a firm organized as a C corporation cannot use the QSBS exclusion on an exit. The two provisions borrow the same list but reach opposite conclusions for these fields.

Salary Optimization Runs the Other Direction

Because the deduction is available, the W-2 wage limitation becomes the binding constraint above the income threshold. The deduction is limited to the greater of 50% of W-2 wages or 25% of wages plus 2.5% of unadjusted basis in qualified property.

That creates a genuine tension with S corporation salary minimization. Lowering owner salary to save payroll tax reduces the wage base and can cost more in lost QBI deduction than it saves.

For a firm with substantial non-owner payroll, the limitation is rarely binding. For a small firm where the owner is most of the payroll, it frequently is, and the optimal salary is higher than payroll tax minimization alone would suggest.

The calculation moves annually with income and payroll and should be run each year rather than set once.

Section 174 Changed and Then Changed Back

The 2017 law required specified research or experimental expenditures under IRC Sec. 174 to be capitalized and amortized over five years for domestic activity, rather than deducted currently, beginning in 2022.

For firms with substantial engineering development activity, that created a cash tax problem disconnected from economics: expenses paid in full but deducted over five years.

Legislation enacted in 2025 restored current deductibility for domestic research expenditures, with transition rules addressing amounts previously capitalized. Foreign research remains subject to a longer amortization period.

Firms that capitalized amounts in 2022 through 2024 should confirm how the transition applies to their unamortized balances, since the mechanism for recovering them affects which year the deduction lands in. This is worth reviewing rather than assuming the prior treatment simply continues.

The Research Credit Is Frequently Available

The credit for increasing research activities under IRC Sec. 41 applies to qualified research undertaken to discover information technological in nature, intended to develop or improve a business component, where substantially all activities constitute a process of experimentation.

Engineering firms frequently qualify on projects involving new structural systems, novel mechanical or electrical designs, energy modeling, geotechnical problem solving, or environmental remediation approaches.

The funded research exclusion is the main obstacle. Research funded by a client through a contract is excluded where the taxpayer does not retain substantial rights and does not bear economic risk of failure. Fixed-price contracts where the firm bears the risk of overruns generally support the credit. Cost-plus contracts generally do not.

Contract terms therefore drive credit eligibility, and firms doing genuine development work should review their standard agreements with this in mind.

Documentation requires project-level tracking of qualified wages, supplies, and contract research, tied to specific business components and a documented process of experimentation. Firms that reconstruct this years later capture far less than firms that track contemporaneously.

Retirement Plans and Firm Demographics

Engineering and architecture firms typically have a small number of high-earning principals and a larger technical staff that skews younger. That is favorable demographics for cross-tested plan design.

A safe harbor 401(k) with new comparability profit sharing directs a large share of employer contributions to the principal group. A cash balance plan layered on top can add $140,000 to $250,000 of annual deductible contribution for a principal over 45.

The interaction with the QBI wage limitation is worth noting. Employer retirement contributions are not W-2 wages, so they reduce qualified business income without increasing the wage base. Where the wage limitation is binding, this can reduce the QBI deduction as it increases the retirement deduction. The two should be optimized together rather than separately.

Worked Example: 34-Person Engineering Firm

A firm has $6,800,000 of revenue and $1,320,000 of profit before principal compensation, with three principals and 31 staff, structured as an S corporation.

Combined principal salaries are set at $780,000, modeled against the QBI wage limitation. Total W-2 wages including staff are $3,900,000, so the 50% wage limitation of $1,950,000 far exceeds the potential deduction and is not binding.

Qualified business income of approximately $540,000 supports a deduction of $108,000, fully available because engineering is not an SSTB.

A research credit study covering fixed-price projects with genuine development content identifies $1,240,000 of qualified research expenses, producing a credit of approximately $86,000.

A safe harbor 401(k) with new comparability directs $210,000 across the three principals at approximately $74,000 of staff cost, and a cash balance plan adds $420,000 across the principals at $61,000 of additional staff cost.

Combined annual tax reduction exceeds $340,000, and the QBI position and research credit both recur.

Frequently Asked Questions

Do engineering and architecture firms qualify for the QBI deduction?

Yes. IRC Sec. 199A(d)(2)(A) expressly excludes engineering and architecture from the specified service trade or business definition, so the deduction is available at any income level, subject to the W-2 wage and qualified property limitations.

Should I lower my salary to save payroll tax?

Not automatically. Above the income threshold, the QBI deduction is limited by W-2 wages, so cutting salary can cost more in lost deduction than it saves in payroll tax. For a small firm where the owner is most of the payroll, the optimal salary is often higher than expected.

Do I still have to capitalize research expenses under Section 174?

Legislation enacted in 2025 restored current deductibility for domestic research expenditures, with transition rules for amounts previously capitalized in 2022 through 2024. Foreign research remains subject to longer amortization. Confirm how the transition applies to your unamortized balance.

Can an engineering firm claim the R&D credit?

Frequently yes, on projects involving genuine technical uncertainty and a process of experimentation. The main obstacle is the funded research exclusion. Fixed-price contracts where you bear overrun risk generally support the credit. Cost-plus contracts generally do not.

Does QSBS apply to an engineering firm?

No. Engineering and architecture remain excluded businesses under IRC Sec. 1202(e)(3), so a C corporation engineering firm cannot use the qualified small business stock exclusion. The two provisions borrow the same list but reach opposite conclusions for these fields.

Tax Strategy for Engineering and Architecture Firms: QBI, Section 174, and the R&D Credit