Apply for R&D tax credit pre-review on Hometax before filing your return

Companies in Korea that claim the tax credit for research and human resources development expenses (연구·인력개발비 세액공제, "the R&D tax credit") can ask the National Tax Service (국세청, NTS) to check, before they file, whether their costs qualify. You apply on Hometax before filing, and you can submit only the projects or costs you want checked. This guide is for founders and finance staff of R&D companies, including foreign-invested ones.

What the pre-review is and why companies use it

The legal basis is Article 9(17) of the Enforcement Decree of the Restriction of Special Taxation Act (조세특례제한법 시행령). A domestic company or resident (내국인) that wants the credit may ask the Commissioner of the NTS (국세청장) to examine in advance whether its spending counts as R&D and human resources development expenses. The request must come before filing the tax base return (the return in paragraph 14 of the same article). The NTS Commissioner sets the method and procedure.

The NTS has run the system since 2020. It is optional. You can claim the credit on your own judgment without a pre-review.

Companies still apply for one reason. Taxpayers and the tax authorities often disagree on whether an activity is R&D and which costs qualify. If a later tax audit finds the claim was wrong, the credited tax can be collected together with penalty tax.

The NTS leaflet (February 2026) lists these benefits:

• Items that were reviewed are excluded from post-filing review (사후관리).
• If you file in line with the result, the under-reporting penalty tax (과소신고가산세) is waived.
• You receive tax credit consulting together with the result.
• Your designated tax agent is also notified of the result.

The benefits do not apply if you submitted inaccurate documents, if the facts change, or if there are signs of omission or tax evasion.

Three ways to apply

Hometax (홈택스) is the NTS website for filing and applications.

There is no eligibility limit. Any domestic corporation or resident that wants the R&D tax credit can apply. The result comes in writing, and if you disagree, you can ask for a re-examination once. For questions, call the NTS Call Center (국세상담센터) on 126, with no area code.

You can split what you submit

Many companies avoid the pre-review because they think every project and every cost must go in. The NTS Q&A says otherwise:

• You can apply for planned costs, not only costs already spent.
• You can pick only some items out of the total costs.
• If the costs are not final, you can ask only whether the R&D activity qualifies.
• You can pick only the projects you want checked.

In practice, start with the projects most likely to be disputed:

• projects that mix government-funded and in-house work
• projects where researchers might appear to do non-research work
• projects with large outsourced research costs
• projects that you want to claim at a higher credit rate as new growth or source technology (신성장·원천기술) or national strategic technology (국가전략기술)

Government projects need special care. According to an example in the NTS leaflet, costs paid from R&D contributions (연구개발출연금) received from the state or similar bodies are not creditable. The private contribution the company bears itself (민간부담금, in cash or in kind) can be credited. If your accounts do not separate the two, this split is hard to prove.

When to apply

The Decree says "before filing". The NTS accepts applications at any time of year, not only near the filing deadline.

For a company with a December year-end, the corporate tax return is due 3 months from the end of the month in which the business year ends, that is, by March 31 (Article 60(1) of the Corporate Tax Act (법인세법)). If you want the result before you file, do not wait for the year-end closing: send the activity review during the business year. Check the processing time when you apply. For a month-by-month plan, see Corporate tax return preparation starts in November.

If the deadline has passed, the order matters. Apply for the pre-review before you file a claim for correction for the omitted items. If the claim for correction goes in first, this window closes.

For SMEs: a related consulting service

Since August 2022 the NTS has also offered consulting on corporate tax credits and reductions. When an SME corporation asks whether it qualifies for employment or investment credits, such as the integrated employment tax credit (통합고용세액공제) or the integrated investment tax credit (통합투자세액공제), and for how much, the NTS answers in writing within 2 months of the application. Filing in line with the consulting brings the same benefits: exclusion from post-filing review and no under-reporting penalty tax. Use the pre-review for R&D and the consulting for employment and investment.

Checklist: documents to prepare

Prepare the same set you file with the corporate tax return under Article 9(14) of the Enforcement Decree: the tax credit application, the statement of R&D and human resources development expenses, and supporting evidence. Then the pre-review carries straight into the return.

• the pre-review application (completed on the Hometax screen)
• the R&D expense statement
• R&D plans and R&D reports
• the recognition certificate for the research institute or dedicated R&D department (연구소·전담부서 인정서)
• the list of dedicated researchers and their appointment documents
• per-project totals for personnel, materials and outsourcing costs
• government project agreements and records separating state contributions from the private contribution

Article 9(13) of the Enforcement Decree delegates the duty to prepare and keep R&D plans, reports and research notes to an Ordinance of the Ministry of Economy and Finance (재정경제부령). Your everyday records become your pre-review file. For registering a research institute or dedicated department, see Corporate research institute registration.