Executive summary
A foreign corporation is generally subject to Korean corporate income tax on its Korean-source income. But determining whether a particular payment is Korean-source income is not always as simple as asking whether the payer is a Korean company.
Korean tax law divides Korean-source income into 10 statutory categories. The classification matters because it can affect the applicable tax treatment, withholding obligations, treaty analysis, and whether the income is connected with a Korean permanent establishment (PE).
This guide covers the first five categories: interest income, dividend income, real estate income, ship/aircraft/equipment leasing income, and business income. A companion guide covers the remaining categories, including personal services, capital gains, royalties, and other Korean-source income.
Who should read this
- Foreign corporations receiving payments from Korea
- Regional and global tax managers reviewing Korean-source income
- Finance teams responsible for Korean withholding tax
- Companies with Korean and overseas operations
- Foreign companies considering whether their Korean activities create taxable business income
- Legal and finance teams reviewing cross-border financing, leasing, distribution, or supply arrangements
The short answer
A foreign corporation may have Korean-source income even when it has no Korean subsidiary.
The first five categories generally work as follows:
| Category | What generally counts as Korean-source income? | Key point |
|---|---|---|
| Interest | Certain interest paid by Korean governments, residents, domestic corporations, or Korean PEs | There is a specific carve-out for certain borrowing by an overseas branch |
| Dividends | Dividends and certain deemed dividends from Korean corporations or qualifying Korean entities | A dividend from a foreign corporation is generally not Korean-source dividend income |
| Real estate | Income from Korean real estate and certain related rights | Disposal gains are classified separately as capital gains |
| Leasing | Income from leasing specified ships, aircraft, vehicles, machinery, equipment, and similar assets to Korean parties | The asset and the lessee both matter |
| Business | Income from specified businesses conducted in Korea, including certain cross-border businesses | Income may need to be apportioned between Korean and foreign activities |
The key practical point is this: Korean-source income is determined by the statutory source rules for the particular type of income — not simply by where the customer or payer is located.
Understanding Korean-source income
1. Interest income
Korean-source interest income generally includes interest and similar income received from:
- The Korean government or a local government
- A Korean resident
- A domestic corporation
- A Korean permanent establishment of a foreign corporation or nonresident
The rule also covers certain interest paid by a foreign corporation or nonresident where the payment is substantially connected with the payer's Korean PE and is deductible in calculating the PE's income.
Korean-source interest generally includes interest falling within the categories of interest income under Korea's Income Tax Act, together with other loan interest and trust profits, subject to statutory exclusions.
A specific carve-out: Korean law excludes interest on a loan directly borrowed by an overseas branch of a Korean resident or domestic corporation for the use of that overseas branch. This can become relevant when analyzing cross-border financing structures involving a Korean head office and overseas operations.
A common first question is "Is the borrower a Korean company?" That is not always enough. The source rule also looks at the identity and location of the relevant business establishment and, in certain cases, whether the interest is attributable to a Korean PE. For multinational groups, the financing structure should therefore be reviewed before applying a blanket "Korean payer = Korean-source interest" approach.
2. Dividend income
Korean-source dividend income generally consists of dividend income paid by:
- A domestic corporation
- An organization treated as a corporation
- Certain other persons located in Korea
The statutory definition incorporates the relevant categories of dividend income under the Income Tax Act and certain amounts treated as dividends under Korean international tax rules. These rules can cover not only ordinary cash dividends but also certain deemed or constructive dividends arising from transactions such as:
- Certain capital reductions
- Dissolution
- Mergers
- Corporate divisions
- Certain distributions of capitalized reserves or similar transactions
- Amounts treated as dividends under specific Korean tax provisions
The taxable amount depends on the particular transaction and the applicable statutory formula.
Foreign dividends are different: a dividend received from a foreign corporation is not automatically Korean-source dividend income merely because the shareholder is a foreign corporation with other Korean activities. The source rule must be applied to the particular payment.
Once a payment is classified as Korean-source dividend income, the analysis is not finished. The next questions may include: is the recipient a treaty resident, does an applicable tax treaty limit Korea's withholding rate, are treaty-benefit requirements satisfied, and is the income connected with a Korean PE? In other words, domestic-source classification and treaty entitlement are two separate questions.
3. Real estate income
Korean-source real estate income includes income arising from the transfer, lease, or other operation of:
- Real estate located in Korea
- Rights relating to Korean real estate
- Certain Korean mining rights
- Quarrying rights
- Rights to extract soil, sand, or stone
- Certain groundwater development or use rights acquired in Korea
Important distinction — rental income vs. disposal gain: one of the most important classification points is that gains from transferring Korean real estate are carved out of this category. They are dealt with separately as Korean-source gains from the transfer of real estate and related assets. Korean real estate rental income and Korean real estate disposal gains should not automatically be analyzed under the same source-income category.
A foreign company may receive both rental income and a gain from selling Korean real estate. Those amounts should not simply be grouped together as "real estate income." Better approach: identify whether the payment arises from ongoing use or operation of the property or from its disposal.
4. Ship, aircraft, and equipment leasing income
Korean-source leasing income includes income from leasing specified assets to Korean residents, domestic corporations, Korean PEs of foreign corporations, and Korean PEs of nonresidents. Covered assets include, among others:
- Ships
- Aircraft
- Registered automobiles
- Construction machinery
- Industrial, commercial, or scientific machinery and equipment
- Certain other tools, instruments, and fixtures specified by law
This category can therefore be relevant even where the lessor itself has no Korean corporation.
For cross-border leasing arrangements, two questions should be asked separately. First, what is being leased — the statutory category is not an unlimited definition of every possible rental arrangement. Second, who is the lessee — the Korean-source rule specifically identifies Korean residents, domestic corporations, and Korean PEs as relevant recipients of the leasing service. The agreement should therefore be reviewed together with the actual asset and parties involved.
5. Business income
Business income is often the most fact-intensive of the first five categories. Korean-source business income generally covers income from businesses conducted in Korea that fall within the business categories referenced by Korean tax law, subject to the separate rules for personal services income. The categories broadly include:
- Agriculture, forestry, and fishing
- Mining
- Manufacturing
- Electricity, gas, steam, and air-conditioning supply
- Water, sewage, waste treatment, and raw-material recycling
- Construction
- Wholesale and retail
- Transportation and warehousing
- Accommodation and food services
- Information and communications
- Finance and insurance
- Real estate
- Professional, scientific, and technical services
- Business facility management, business support, and rental services
- Education
- Health and social welfare
- Arts, sports, and leisure
- Associations, organizations, repair, and other personal services
- Household employment activities
- Certain disposals of business-use tangible assets by qualifying taxpayers
- Similar income from continuous and repeated profit-making activities conducted on the taxpayer's own account and responsibility
The precise statutory classification should be checked against the taxpayer's actual activities rather than simply the company's registered business description.
How cross-border business income is allocated
A particularly important issue arises when the same business is conducted partly in Korea and partly outside Korea. Korean tax rules contain specific allocation rules for several types of cross-border business.
Inventory. Special rules apply where inventory is manufactured or otherwise value-enhanced outside Korea and then sold in Korea, or where goods manufactured in Korea are sold abroad. The Korean-source portion may depend on what income would have arisen from an arm's-length acquisition or sale between independent parties. This means that the location of the final customer is not necessarily enough to determine the amount of Korean-source income.
Construction and installation. Where a foreign corporation contracts for construction, installation, assembly, or similar work outside Korea but procures personnel or materials and performs the work in Korea, specific rules may treat the resulting income as Korean-source.
Insurance. For insurance businesses operated across Korea and other jurisdictions, the Korean-source portion can be determined by reference to insurance contracts entered into through a Korean business office or an authorized agent in Korea.
Publishing and broadcasting advertising. For foreign publishing or broadcasting businesses conducting advertising activities across Korea and overseas, the rules look to advertising activities actually carried out in Korea. The location of the customer or payment alone does not necessarily determine the source of the income.
International transportation. Special allocation rules apply to international shipping and air transportation. For international shipping, the allocation can be based on revenue associated with passengers boarding or cargo loaded in Korea. For international air transportation, a formula considers Korean-related revenue and other factors reflecting the contribution of Korean operations.
Other cross-border businesses. For businesses not covered by the specific allocation rules, Korean-source income may be determined by separating the Korean and foreign activities and considering what income would arise if the two operations were carried on by independent businesses dealing with each other on arm's-length terms. This is where functional analysis, revenue, expenses, assets, personnel, and the actual activities performed in Korea can become particularly important.
Practical insight: Korean-source income is not the same as Korean revenue
For multinational companies, one of the most common mistakes is to assume: "Revenue from Korean customers = Korean-source income." That shortcut can produce the wrong answer.
Where the relevant activity takes place, which entity performs the activity, whether a Korean PE is involved, where manufacturing or value enhancement occurs, where contracts are negotiated or concluded, which assets and personnel contribute to the income, and whether a specific statutory allocation formula applies. The question is therefore not simply "where is the customer?" It is "what activity generated the income, and where was that activity carried out?"
What foreign companies often get wrong
- Assuming a Korean payer automatically creates Korean-source income. A payment from a Korean company is an important fact, but it does not replace the statutory source analysis. Better approach: start with the type of income and then apply the specific source rule.
- Treating Korean-source income and PE income as the same concept. A foreign corporation can have Korean-source income without necessarily having a Korean PE. Conversely, once a Korean PE exists, additional questions arise concerning which income is attributable to that PE. Better approach: analyze source of income and existence/attribution of a PE as related but separate questions.
- Assuming all cross-border business profit is either 100% Korean or 100% foreign. Where business activities span Korea and other jurisdictions, Korean law provides specific allocation rules for several types of business. Better approach: check the business-specific allocation rule before applying a simple revenue-based allocation.
- Treating real estate rental income and disposal gains as the same category. Korean real estate rental or operating income and gains from transferring Korean real estate are subject to different source-income classifications. Better approach: identify the transaction that generated the income before determining the applicable tax regime.
- Looking only at the contract or invoice. The legal contract and invoice are important, but they may not tell the entire story. For cross-border businesses, the actual functions performed by Korean personnel, the location of assets, negotiations, manufacturing, and other operational facts can affect the source analysis. Better approach: review the actual business model, not just the legal documentation.
Frequently asked questions
Does receiving payment from a Korean company automatically make income Korean-source?
No. The payer's location is relevant, but Korean-source income is determined under the specific statutory rule applicable to the type of income.
Can a foreign corporation have Korean-source income without having a Korean PE?
Yes. Korean-source income and the existence of a Korean PE are separate concepts. Certain Korean-source income may be subject to withholding even where the foreign corporation has no Korean PE.
Is Korean-source income always subject to Korean withholding tax?
Not necessarily. The withholding rules depend on the category of income and whether the income is connected with or attributable to a Korean PE. A tax treaty may also modify Korea's taxing rights or withholding rate.
Is income from selling Korean real estate treated as real estate income?
Not for this purpose. Gains from transferring Korean real estate and certain related rights are dealt with under the separate Korean-source capital-gain category.
How is cross-border business income allocated between Korea and other countries?
It depends on the type of business. Korean law provides specific allocation rules for areas such as inventory, construction, insurance, advertising, and international transportation. Other businesses may require an arm's-length analysis of Korean and foreign operations.
Does a Korean customer automatically mean the foreign company's business profit is Korean-source?
No. The source analysis focuses on the nature and location of the activities generating the income, not simply the customer's location.
Practical checklist
Before concluding that a payment is Korean-source income, ask:
- What type of income is this?
- Which Korean-source income category applies?
- Who is the payer?
- Where is the payer located?
- Does the payer have a Korean PE?
- Where was the activity that generated the income actually performed?
- Is the income connected with a Korean PE?
- Does a specific cross-border allocation rule apply?
- Is there an applicable tax treaty?
- If withholding applies, is a treaty-reduced rate available?
- Are the documentation and withholding requirements satisfied?
Key takeaways
For foreign corporations, determining Korean-source income is a classification exercise first and a tax-rate exercise second. The most important questions are: what type of income is being received, what statutory source rule applies to that type of income, where were the activities generating the income actually performed, is there a Korean PE and if so is the income attributable to it, and does a tax treaty change Korea's taxing rights or withholding rate?
For multinational groups, the difficult part is often not finding the Korean tax rate. It is determining which income Korea is entitled to tax in the first place.
Related guides
- Korean-Source Income for Foreign Corporations: Personal Services, Capital Gains, Royalties, and Securities
- What Counts as a Permanent Establishment in Korea?
- Withholding Tax in Korea: What Foreign Businesses Need to Know (coming soon)
- Korea Tax Treaties: Claiming a Reduced Withholding Rate (coming soon)
- Branch vs. Subsidiary vs. Liaison Office in Korea