§174 R&D Expensing Restored: §174A and the OBBBA Retroactive Fix

How TCJA broke R&D treatment

From 1954 through 2021, businesses could deduct research and experimental (R&E) expenditures in the year incurred under former §174 — software developers, R&D-intensive startups, and manufacturers treated salaries, contractor fees, cloud costs, and supplies as ordinary expenses. TCJA's revenue-offset provision (effective for tax years beginning after 12/31/2021) eliminated immediate expensing and required: • Domestic R&E → 5-year straight-line amortisation • Foreign R&E → 15-year straight-line amortisation • Half-year convention in year of acquisition (so 10% in year 1, 20% in years 2–5, 10% in year 6) For a cash-strapped startup spending $2M on engineering salaries, the change meant deducting $200,000 instead of $2,000,000 in year 1 — creating phantom income, tax bills with no cash to pay them, and forcing layoffs. The provision drew bipartisan condemnation almost immediately and was the single most-lobbied tax-fix item from 2022 through 2025.

OBBBA §174A: immediate expensing restored

OBBBA enacted new IRC §174A effective for tax years beginning after 12/31/2024: • Domestic R&E: fully deductible in the year paid or incurred (back to the pre-TCJA treatment) • Foreign R&E: remains on the 15-year amortisation schedule — political compromise that preserves some of the original revenue offset 'Domestic' means R&E performed in the United States (and territories). Where the costs are paid TO is irrelevant; where the work is performed governs. For software development specifically, the legislation clarifies that software-development costs incurred in the US qualify for §174A immediate expensing, settling years of post-TCJA ambiguity.

The retroactive small-business window

For taxpayers with average annual gross receipts of $31 million or less (the §448(c) small-business threshold) for the prior 3 years, OBBBA provides retroactive relief covering the broken 2022, 2023, and 2024 tax years. Two paths: **Path 1 — Amended returns**: File amended 2022, 2023, and 2024 returns claiming full expensing under the restored treatment. Recover overpaid tax via refund. **Path 2 — Accelerated catch-up on 2025 or 2026 return**: Elect to deduct ALL remaining unamortised 2022–2024 domestic R&E on the 2025 return, OR spread over 2025 and 2026. Avoids amended-return administrative burden. Larger businesses (>$31M avg gross receipts) do NOT get retroactive relief — they continue amortising 2022–2024 R&E over the original 5-year schedule, but get the immediate-expensing treatment going forward for 2025+ costs.

Interaction with the §41 R&D Credit

The §41 Research Credit is separate from §174 deduction treatment. Both are available simultaneously, but coordinated under IRC §280C(c)(2): • By default, claiming the §41 credit reduces the §174 / §174A deduction dollar-for-dollar by the credit amount • Alternatively, the taxpayer may elect under §280C(c)(2) for a 'reduced credit' (credit × (1 − maximum federal corporate rate, currently 21%) = credit × 0.79) and keep the full deduction The reduced-credit election usually benefits taxpayers in the 21% federal corporate bracket or those with state credit coordination concerns. Always model both paths for the specific year.

Documentation that survives §41 audit

Both §174A and §41 require documenting that costs meet the qualified research definition: experimentation, technological in nature, intended to discover information that eliminates uncertainty, and resulting in a new or improved business component. Project-level documentation should include: • Nature of uncertainty being resolved • Process of experimentation followed • Technological nature of the research • Time-tracked allocation of employee/contractor hours to qualifying projects IRS Audit Technique Guide for Research Credit Claims (2023 update) sets out the substantiation standards. Routine software maintenance, UI redesign, or post-deployment debugging generally does NOT qualify.

Worked example: Wavefront Robotics, Inc. (C-corp, $4.2M avg gross receipts)

Wavefront spent $1,800,000 of domestic R&E in 2022, $2,100,000 in 2023, $2,400,000 in 2024, and $2,800,000 in 2025. The company is a §448(c) small business. Modeling the retroactive catch-up options under OBBBA on the 2025 return.

Pre-OBBBA amortisation already taken (5-year SL, half-year convention): 2022 R&E $1.8M: deducted 180k (2022) + 360k (2023) + 360k (2024) = 900,000. Remaining: 900,000. 2023 R&E $2.1M: deducted 210k (2023) + 420k (2024) = 630,000. Remaining: 1,470,000. 2024 R&E $2.4M: deducted 240k (2024) = 240,000. Remaining: 2,160,000. Total unamortised at start of 2025: 900,000 + 1,470,000 + 2,160,000 = 4,530,000. Option A — amend 2022, 2023, 2024 returns: Each year recomputed with full expensing, refund claimed for overpaid tax. Administrative burden but cleanest result. Refunds ~21% × (full expense − amortised amount) per year. Option B — full catch-up on 2025 return: 2025 deductions: Catch-up of unamortised 2022–2024: 4,530,000 Current 2025 domestic R&E expense: 2,800,000 Total §174A deduction: 7,330,000 Election filed with 2025 return. Option C — 2-year spread (2025 + 2026): 2025: catch-up 2,265,000 + current 2,800,000 = 5,065,000 2026: catch-up 2,265,000 + 2026 R&E expense Decision factors: 2025 taxable income (capacity to absorb $7.3M deduction), §41 credit coordination, NOL implications.

Statute references

• Restored domestic R&E immediate expensing — IRC §174A (added by OBBBA)
• TCJA capitalisation rule (still applies to foreign R&E) — IRC §174
• Research credit — IRC §41
• Reduced-credit election — IRC §280C(c)(2)
• Small-business gross-receipts threshold — IRC §448(c) ($31M for 2026)

Related pages

• R&D Tax Credit Calculator (§41) →
• Tax Changes 2026 Guide →
• NOL and Business Losses Guide →