Large sole traders in Korea file income tax not in May but by 30 June, and they must attach a tax review report in which a tax accountant or similar confirms, from the books and evidence, that business income is properly stated. That’s Income Tax Act Article 70-2. It covers businesses whose revenue for the year reaches the Decree Article 133 line — 1.5 billion, 750 million or 500 million won by sector.
1. Revenue this year of 1.5bn, 750m or 500m won or more (by sector) means a review report.
2. File from 1 May to 30 June of the next year, with the report.
3. Business services listed in Annex 3-3 use the 500 million won line even in sectors 1 and 2.
Who — Decree Art. 133(1)
| Sector (Art. 133(1)) | Revenue line (or more) | Worth noting (ours) |
|---|---|---|
| 1 · Farming, mining, wholesale/retail (excl. brokerage), property trading, others | 1.5 billion won | — |
| 2 · Manufacturing, food and lodging, utilities, construction (excl. non-residential, incl. residential development), transport, ICT, finance, brokerage | 750 million won | — |
| 3 · Property letting, real estate, professional and technical, business support, education, health and social work, arts and sports, associations, personal services, household employment | 500 million won | — |
Revenue is this year’s total, excluding sales of business fixed assets. Business services in Annex 3-3 use the 500 million won line even in sectors 1 and 2 (proviso). Mixed businesses or several premises convert revenue under Art. 208(7) (para. 2).
What and when — Act Art. 70-2
| Type | What the source says | Worth noting (ours) |
|---|---|---|
| Review | A report on whether business income computed from books and evidence is proper, by a tax accountant or similar | Tax accountants, registered CPAs etc. (Decree para. 3) |
| Filing | In addition to the usual return documents, to the tax office | — |
| Period | 1 May to 30 June of the next year (para. 2) | Ordinary returns end 31 May |
| Corrections | The tax office may require corrections (para. 3) | — |
Our examples
| Business (this year’s revenue) | Review report | Worth noting (ours) |
|---|---|---|
| Restaurant, 800m (sector 2) | Required | 750m or more |
| Tutoring academy, 490m (sector 3) | Not required | Under 500m |
| Wholesale, 1.2bn (sector 1) | Not required | Under 1.5bn |
For book type and simple-rate lines as well, use the bookkeeping checker. Ordinary filing is in global income tax.
Checklist
- ☐ This year’s revenue at or above your line?
- ☐ Business services: 500 million won
- ☐ Mixed businesses: convert revenue
- ☐ Book a reviewer early
- ☐ File by 30 June
Questions that remain
What if I don’t submit the report?
Penalties aren’t in the articles we read (Art. 70-2, Decree Art. 133); they sit elsewhere.
Is the review fee deductible?
These articles cover only filing the report; any credit for the fee is in other law, outside this post.
Sources
- Korean law database (law.go.kr) — Income Tax Decree Art. 133 — source (current text, effective 1 October 2026, No. 36737; checked 19 October 2026). Sectors and the 1.5bn, 750m and 500m lines, business-services proviso, mixed businesses, reviewers, 30 June, corrections.
- Korean law database — Income Tax Act Art. 70-2 (effective 1 July 2026).
- Not read. The Annex 3-3 list, non-filing penalties, fee credits.
- What we added. The “worth noting” column and the Korean everyday gloss.
Where to check further
- NTS Hometax — review report guidance.
Written on 19 October 2026. The content is from the source; the glosses are ours.
