Claiming the Credit for Past Years: Amended Returns and the §174 Lookback

If you have only ever thought about the R&D credit as a current-year decision, you are missing half of it. The credit can be claimed for past years too, and a separate change to §174 means many software companies overpaid tax on their 2022 through 2024 returns and may now be owed a refund. For eligible small businesses, the window to fix those returns is closing in mid-2026, so this is time-sensitive. Here is how claiming for past years works, and why 2022 to 2024 specifically matter right now. Claiming the Credit for Prior Years You are not limited to the current tax year. You can claim the R&D credit retroactively for open tax years, which generally means the last three years under the normal statute of limitations, and sometimes longer in certain loss situations. The mechanism is an amended return for each year you are correcting. A few rules shape how this works:To claim a refund on an amended return, the IRS requires project-level, business-component detail for the §41 claim. A vague "we did R&D" will not support a refund claim; you need to show which components the work tied to. Unused credits do not disappear. Under §39, they carry forward up to 20 years, and they can generally be carried back one year.So if your company was doing qualifying engineering work in prior years but never claimed the credit, those open years may still be recoverable. The specifics of which years are open for you depend on your filing history, so confirm with a CPA for your situation. Why 2022 to 2024 Are Different: The §174 Trap There is a second, larger reason to look at 2022 through 2024, and it has to do with §174, the deduction side of research spending. For decades, companies could deduct research costs in the year they spent the money. The Tax Cuts and Jobs Act changed that. Starting with tax years after December 31, 2021, companies were required to capitalize and amortize research costs instead of deducting them immediately, domestic costs over 5 years and foreign costs over 15. Because you could no longer write off your full engineering spend in the year it occurred, your taxable income looked artificially high, which inflated tax bills for 2022, 2023, and 2024. This is what people call "the §174 trap." It hit software companies hardest because engineering payroll is often the single largest expense, and almost all of it is research spending. Founders frequently described being taxed on money they had already paid out in salaries. That is essentially what capitalization created. The Reversal and a Closing Window The trap has now been partly undone. The One Big Beautiful Bill Act (OBBBA), signed July 4, 2025, created new §174A and restored immediate expensing of domestic research costs for tax years beginning after December 31, 2024. For small businesses, the relief reaches backward, and this is the part with a deadline:Small businesses, defined as those with average annual gross receipts of $31 million or less under §448(c), can elect §174A retroactively and amend their 2022 through 2024 returns for refunds. The window is tight. It generally runs until one year from the law's July 2025 enactment, which lands on July 6, 2026 (the next business day after the one-year mark). The IRS guidance on how to do this is in Revenue Procedure 2025-28.One important limit remains: foreign research costs still must be capitalized, over 15 years. The restored immediate expensing applies to domestic research. How OBBBA and the retroactive election apply to your company is fact-dependent, so confirm the specifics with a CPA. The Founder Takeaway There are really two things to check here, and they often travel together. First, if you did qualifying engineering work in prior open years and never claimed the §41 credit, an amended return may still recover it, with the project-level detail the IRS requires. Second, if the §174 capitalization rules inflated your 2022 through 2024 taxes, you may be owed a refund, and for small businesses the amend window closes in mid-2026. Both are backward-looking opportunities that quietly expire. Sorting through whether either applies to you, before the §174 small-business window closes on July 6, 2026, is exactly the kind of review TaxUpside helps SaaS companies run. This is general information, not tax advice. Eligibility, open years, and the retroactive election all depend on your specific facts, so confirm with a qualified CPA before relying on any of it.