One Decision, Two Rulebooks: How Tax Planning Can Affect Your AEC Firm’s Overhead Audit

Tax planning and overhead-rate planning start with the same general ledger. They don’t always end up in the same place.

For architecture, engineering, and construction (AEC) firms performing government contract work, a tax strategy that saves real money on a tax return can unexpectedly affect the overhead schedule. In other cases, it may not affect the overhead rate at all.

Neither outcome necessarily means someone made a mistake. It means the Internal Revenue Code (IRC) and the Federal Acquisition Regulation (FAR) ask entirely different questions:

• The tax return asks: How much income is taxable?
• The overhead schedule asks: Which costs are allowable, where do they belong, and are they reasonable?

Those aren’t the same conversation, and understanding the difference is an important part of effective tax planning for government contractors.

Is a Tax Deduction Automatically an Allowable Overhead Cost?

No. A tax deduction is not automatically an allowable overhead cost, nor is an allowable overhead cost required to be deductible in the same year. Tax rules under the Internal Revenue Code (IRC) govern taxable profit, while the Federal Acquisition Regulation (FAR) governs cost allowability and allocability on government contracts.

Federal income taxes are the clearest example. They are expressly unallowable for overhead purposes under FAR 31.205-41. A strategy that reduces a firm’s federal income tax can therefore produce real cash savings without moving its overhead rate at all. That is the easy case. More complicated situations arise when one decision affects both calculations in different ways. Capital purchases and year-end bonuses are two examples where the timing, accounting treatment, allowability, and documentation can all matter.

Capital Purchases: One Purchase, Two Timelines

Suppose your firm purchases $120,000 of equipment and deducts the entire cost on its tax return this year. That may help the tax bill, but it doesn’t mean $120,000 belongs in the overhead pool.

Allowable depreciation for overhead purposes generally follows the firm’s financial-accounting treatment and consistently applied depreciation policies, not the accelerated deduction claimed on the tax return. Under FAR 31.205-11, the same purchase could produce a $120,000 tax deduction but only $15,000 of current-year depreciation expense for overhead purposes: same equipment, same ledger, two different clocks.

Same Equipment. Same Ledger. Two Different Clocks.

That distinction can matter when firms evaluate the impact of a major capital investment on their overhead rate. A tax strategy that improves current-year cash flow may not have the same immediate effect on indirect costs or billing rates.

The planning question isn’t simply, “Should we buy the equipment?” It is also, “What will this do to our taxes, books, cash flow, and overhead rate?”

Ideally, that conversation happens before the purchase is made and recorded, rather than after the year-end overhead schedule is prepared.

Year-End Bonuses: The Entry Isn’t the Whole Story

Year-end bonuses are another area where tax and FAR considerations can diverge.

Bonuses paid as compensation for services generally may be deductible for tax purposes. The timing of the deduction, however, depends on the firm’s tax method, when the liability becomes fixed, when the bonus is paid, and whether the recipient is a related party.

For FAR purposes, bonuses generally must arise from a good-faith agreement established before the services were performed or from an established plan or policy that the firm has followed consistently. The basis for the awards also needs to be supported.

For an owner, there is another question:

Is the bonus reasonable compensation for services, or is it a profit distribution wearing a bonus costume?

A year-end journal entry doesn’t answer those questions on its own. If bonuses are included in the overhead calculation, the firm should be prepared to support the history, calculation, and business rationale behind them, not just the entry or the payment.

This is where documentation and consistency become particularly important. How a firm has historically structured and supported compensation decisions can matter as much as the entry appearing in the general ledger.

What Should AEC Firms Consider Before Implementing a Tax Strategy?

AEC firms performing government contract work should evaluate the tax and overhead implications of a strategy together, not as two separate year-end exercises. “Deductible” and “allowable” aren’t the same word, wearing different hats. Neither are “credit” and “reimbursement.”

Before implementing a tax strategy, consider questions such as:

• Does this strategy change the accounting records or only the tax return?
• Which direct or indirect cost pool does it affect?
• Is the treatment consistent with the firm’s established practices?
• Does a credit or reimbursement relate to a cost included in overhead?
• Is there a paper trail an auditor will actually want to see?

None of this means leaving tax savings on the table. It means evaluating both results before the transaction hits the books, not after someone starts asking questions. For AEC firms, that means bringing tax planning, accounting, and government contract considerations into the same conversation. A strategy that looks attractive from one perspective may look very different when viewed through the lens of an overhead audit.

Want to Take a Closer Look at Allowable Overhead?

Tax planning can create opportunities, but government contractors need to evaluate those opportunities alongside the rules governing allowable costs and overhead.

Join us for our webinar, Maximizing Allowable Overhead: Strategic Tax Planning for Government Contractors, where we’ll explore how tax decisions intersect with overhead calculations and what government contractors should consider before year-end.