Section 174 explained: from full expensing to amortization and back

For nearly seventy years, Section 174 was one of the least controversial provisions in the Code: research and experimental expenditures were deductible in the year paid or incurred, full stop. That ended for tax years beginning in 2022, when a delayed provision of the Tax Cuts and Jobs Act converted Section 174 into a mandatory capitalization regime — five-year amortization for domestic research, fifteen-year for foreign, with software development swept in by statute. Three years of cash-tax pain later, the One Big Beautiful Bill Act (OBBBA), enacted July 4, 2025, restored immediate expensing for domestic research through a new Section 174A, effective for tax years beginning after December 31, 2024.

This guide covers the full arc: what Section 174 reaches, how the 2022–2024 amortization era actually hit taxable income, and what the restoration does and does not fix.

What Section 174 covers: SRE expenditures

Section 174 applies to "specified research or experimental expenditures" — SRE expenditures, in the argot. The core definition predates the TCJA: expenditures incurred in connection with the taxpayer's trade or business which represent research and development costs "in the experimental or laboratory sense." Treas. Reg. §1.174-2 glosses this as activities intended to discover information that would eliminate uncertainty concerning the development or improvement of a product — where "uncertainty" exists if the information available does not establish the capability or method for developing the product, or its appropriate design.

Several features distinguish 174 from an ordinary business deduction under Section 162:

• Breadth. Section 174 does not require success, novelty to the industry, or a formal R&D department. Uncertainty about capability, method, or design is enough.
• No trade-or-business ripeness requirement. Under Snow v. Commissioner, 416 U.S. 500 (1974), pre-revenue startups can have 174 costs even before an active trade or business exists in the Section 162 sense.
• Indirect costs count. Notice 2023-63 confirmed that SRE expenditures include allocable overhead — rent, utilities, depreciation, and labor costs of employees who support research — not just the direct costs a company books to an R&D cost center. We cover the allocation mechanics in identifying SRE expenditures.

The TCJA added one categorical rule: for tax years beginning after 2021, "any amount paid or incurred in connection with the development of any software" is treated as an SRE expenditure. No uncertainty analysis required; software development is 174 by fiat. That single sentence is why the 2022–2024 era hit the technology sector hardest — see why software was swept into Section 174.

The pre-2022 world: expensing by default

Before 2022, Section 174 offered a choice: deduct research costs currently, or elect to capitalize and amortize over not less than 60 months. Nearly everyone deducted. Software development enjoyed parallel comfort under Rev. Proc. 2000-50, which allowed current deduction of software development costs "in a manner similar to" Section 174. The distinction between 174 costs and ordinary 162 expenses rarely mattered on the deduction side; it mattered mainly as the gateway to the Section 41 research credit.

The TCJA, enacted in December 2017, scheduled the switch to mandatory amortization for tax years beginning after December 31, 2021 — a revenue-raiser placed four years out, which most observers expected Congress to repeal before it took effect. Congress did not.

The amortization era, 2022–2024

For tax years beginning in 2022 through 2024, capitalization was mandatory:

• Domestic SRE expenditures: amortized over 5 years.
• Foreign SRE expenditures (research performed outside the United States, its possessions, and territories): amortized over 15 years.
• Midpoint convention: amortization begins at the midpoint of the year the costs are incurred, so year one yields only a half-year of deduction — 10% of a domestic cost, 3.33% of a foreign one.
• No recovery on disposition: abandoning a project or even disposing of the underlying property did not accelerate the write-off; amortization continued on schedule.

A worked example: the cash-tax shock

Consider a domestic software company with $10 million of revenue, $6 million of SRE expenditures (all domestic engineering payroll and allocable overhead), and $3 million of other deductible operating costs. Book income is $1 million. Here is taxable income in the first amortization year under each regime.

The same economic year produces radically different taxable income under expensing versus first-year amortization:

The amortization-year deduction is $600,000 — 10% of the $6 million, reflecting the half-year midpoint convention. The company's tax bill is 6.4 times higher on identical economics. A pre-revenue startup fared worse still: a company with no revenue and $6 million of research spend, which previously showed a $6 million loss, could show positive taxable income once salaries capitalized under 174 exceeded its remaining deductions. The deductions were not lost — they were deferred across the five-year schedule — but the year-one cash outflow was real, and for companies without financing, sometimes existential. Growing R&D budgets meant the wedge compounded each year rather than washing out.

State conformity varied: some states never adopted TCJA capitalization, so companies ran parallel computations for three years.

The 2025 restoration: Section 174A

The OBBBA did not simply repeal the TCJA change. It enacted a new Section 174A governing domestic research or experimental expenditures for tax years beginning after December 31, 2024:

• Immediate deduction of domestic R&E expenditures, restoring the pre-2022 default.
• Elective capitalization over not less than 60 months, for taxpayers who prefer to spread deductions — relevant where a company wants to preserve income against expiring attributes or Section 382-limited NOLs.
• Foreign research unchanged: SRE expenditures attributable to research performed outside the United States remain capitalized over 15 years under Section 174 itself. The old section survives as the foreign-research regime — see the 15-year foreign rule.

The full mechanics — including what makes research "domestic," and how 174A interacts with the research credit and Section 280C — are covered in Section 174A explained.

Transition relief for 2022–2024 balances

Amounts capitalized during the amortization era do not automatically spring back. The OBBBA offers a menu:

1. Small-business retroactivity. Taxpayers meeting the Section 448(c) gross-receipts test at a $31 million threshold (average annual gross receipts for the prior three years) may apply Section 174A retroactively to tax years beginning after December 31, 2021 — amending 2022, 2023, and 2024 returns to deduct the costs as if capitalization never applied.
2. Catch-up deduction for everyone. All taxpayers may deduct remaining unamortized domestic Section 174 amounts over one or two tax years, beginning with the first tax year after 2024 — typically 2025 for calendar-year filers.

Both paths involve accounting-method-change mechanics; the choice between them turns on rates, NOL posture, and refund interest. We model the trade-offs in the transition rules guide and, for small businesses specifically, in amended return vs. catch-up.

Section 174 and the Section 41 research credit

Section 174 and Section 41 are frequently conflated. They are different instruments doing different work.

Section 174 (and now 174A) governs the deduction — the timing of cost recovery. Section 41 provides a credit — a dollar-for-dollar tax reduction computed on qualified research expenses (QREs). The two are linked at the definition: an expense can be a QRE only if it is first eligible under Section 174. Section 41(d)'s four-part test then narrows the pool substantially — technological in nature, process of experimentation, permitted purpose — and the credit reaches only certain cost categories (in-house wages, supplies, 65% of most contract research), not the overhead that 174 sweeps in.

Two practical consequences:

• A company's 174 cost pool is almost always larger than its Section 41 QRE pool. During the amortization era, this asymmetry stung: overhead had to be capitalized under 174 without generating any credit.
• Section 280C polices double benefit. A taxpayer claiming the credit must either reduce its deduction (or capitalized amount) by the credit, or elect a reduced credit under Section 280C(c). With full expensing restored, the 280C computation once again operates against a current deduction rather than an amortization schedule.

For a fuller treatment, see Section 174 vs. Section 41 and the primer on what the R&D credit is.

Where disputes still arise

Restoration of expensing lowers the temperature but does not end controversy under 174.

• Domestic vs. foreign classification. With a 15-year schedule still attached to foreign research, the situs of research activity — including where contract researchers actually perform work — is now the highest-stakes classification question in the section.
• Scope creep in both directions. Before 2022, taxpayers wanted costs in 174 (credit eligibility); during 2022–2024, they wanted costs out (avoid capitalization); now the incentives have largely realigned, but amended-return positions for the capitalization years still get examined. The IRS challenges aggressive re-characterization of 2022–2024 costs as Section 162 expenses, particularly routine software maintenance recast as non-developmental.
• Transition elections. Method-change filings and small-business amended returns each carry their own procedural traps — see Section 481(a) and Section 174 and the general Form 3115 guide.

The bottom line

Section 174 is now a two-track regime. Domestic research or experimental expenditures — including domestic software development — are deductible as incurred under Section 174A, with an election to amortize over at least 60 months for those who want it. Foreign research stays on a 15-year clock under Section 174 proper. The 2022–2024 capitalization era survives only in its residue: unamortized balances working through the transition rules, amended-return refund claims for small businesses, and a body of guidance (chiefly Notice 2023-63) that continues to define what an SRE expenditure is. For CPAs, the compliance question has shifted from "how do we amortize this" to "where was this research performed, and which transition path recovers the stranded balance fastest."