How to Report Korean Bank Interest on Your U.S. Tax Return
한국 은행 이자소득 미국 세금 신고 완전 가이드 — 2026

Overview — Which Korean Interest Is Taxable 어떤 한국 이자소득이 미국에서 과세되는가

U.S. tax residents must report worldwide income — including interest earned on Korean bank accounts, savings accounts (적금), CMA accounts, and fintech accounts. Korean interest income is taxable in the U.S. for the period during which the taxpayer was a U.S. tax resident, regardless of whether Korea already withheld tax at the source.

Korean Withholding Rate — Corrected Breakdown 한국 원천징수 세율 — 정확한 구성

• Both components are creditable on U.S. Form 1116: The 14% national income tax and the 1.4% local income tax are both legally imposed income taxes paid to Korean government authorities. Both qualify as "foreign income taxes" for U.S. Foreign Tax Credit purposes. The full 15.4% withheld is creditable.
• Korean withholding is a final tax for most interest income: For Korean residents, the 15.4% withholding on bank interest is typically a "separate taxation" (분리과세) final withholding — the interest is not included in the annual comprehensive income tax return (종합소득세). This means the 이자소득 원천징수영수증 showing 15.4% withheld is the primary documentation for the FTC claim.
• Korean national pension (건강보험 / 국민연금) premiums are NOT creditable: Social insurance contributions paid to Korea — health insurance (건강보험) and national pension (국민연금) — are not income taxes and cannot be claimed as Foreign Tax Credit on Form 1116. Only the 소득세 (14%) and 지방소득세 (1.4%) qualify.

Timing — Residency Period Interest Only 거주자 기간 이자만 미국 과세

Only interest earned during the U.S. tax residency period is reportable on Form 1040. Interest accrued before the residency start date belongs to the non-resident period and is not subject to U.S. tax.

Regular Interest — Monthly / Quarterly Credit

For accounts where interest is credited monthly or quarterly (일반 예금 이자), the U.S. taxable portion is straightforward: only the amounts credited to the account on or after the residency start date. Interest credited in January through March (if residency started April 1) is not reportable to the IRS.

Korean Installment Savings (적금) — Apportionment Required

Exchange Rate — Which Method to Use 환율 변환 방법

Korean won (KRW) interest income must be converted to U.S. dollars for Schedule B reporting. The IRS does not mandate a single method but requires consistent application throughout the return.

Schedule B — How to Report Schedule B 이자소득 신고 방법

Korean bank interest is reported on Schedule B (Interest and Ordinary Dividends), which is attached to Form 1040. Schedule B has three parts — Korean bank interest appears in Part I, and Korean accounts trigger a specific disclosure requirement in Part III.

Part I — Interest Income (Korean Banks)

Part III — Foreign Account Disclosure Question

• Always answer "Yes" to Part III Question 7a if you have Korean accounts: Any U.S. tax resident who holds Korean bank, brokerage, savings, or fintech accounts must check "Yes" — regardless of the account balance. Checking "No" when Korean accounts exist is a false statement on a federal tax return and can be used as evidence of willfulness in FBAR enforcement proceedings.
• Part III does not replace FBAR: Checking "Yes" on Schedule B Part III is not a substitute for filing the FBAR (FinCEN Form 114). Both are required independently. Schedule B records the existence of foreign accounts within the income tax return; the FBAR is a separate FinCEN filing with account-specific details (institution name, account number, maximum balance).
• Include all Korean accounts even if below $10,000: The Schedule B Part III question asks about any foreign financial account — there is no dollar threshold. Even a dormant Korean account with $200 requires "Yes" in Part III. The $10,000 threshold applies to the FBAR filing requirement, not the Schedule B disclosure.

Form 1116 — Foreign Tax Credit (Passive Basket) 외국납부세액공제 — 수동적 소득 바스켓

Korean bank interest withholding (15.4%) generates a Foreign Tax Credit that prevents double taxation. This credit is calculated on Form 1116 — but critically, Korean bank interest belongs to the passive income basket, which is calculated separately from wages and business income (general basket).

Passive Basket vs. General Basket

• Korean bank interest → passive income basket: Interest income is classified as "passive category income" for Form 1116 purposes. The FTC for Korean bank interest is calculated on a separate Form 1116 specifically for the passive basket — not combined with the Form 1116 for Korean salary (which is general basket income).
• The two baskets cannot offset each other: If excess FTC exists in the general basket (e.g., Korean income taxes on salary exceed the U.S. tax on that salary), those excess credits cannot be applied to reduce U.S. tax on interest income in the passive basket. Each basket is calculated separately.
• FTC limitation on passive income: The FTC is capped at the proportional U.S. tax on the foreign passive income. Since Korean bank interest withholding (15.4%) typically exceeds the U.S. tax rate on the same income (e.g., 22%), the excess FTC generally cannot be used in the current year but carries back 1 year and forward 10 years.
• Both 14% and 1.4% are creditable: The full 15.4% Korean withholding — including both the national income tax and the local income tax — qualifies as a creditable foreign income tax on Form 1116. Social insurance premiums (국민연금, 건강보험) are not creditable.

FBAR & FATCA Connection FBAR · FATCA 연계 의무

Reporting Korean interest on Schedule B satisfies the income tax reporting obligation — but it does not replace or satisfy the separate FBAR and FATCA filing requirements. All three obligations are independent.

Step-by-Step Filing Checklist 단계별 신고 체크리스트

5 Case Examples 실제 사례 5개

Documentation Checklist 필요 서류 목록

Collect these documents from Korean banks before year-end or before filing. Requesting Korean tax documents from the U.S. after filing may be difficult.

• 이자소득 원천징수영수증(Interest Income Withholding Certificate) — from each Korean bank, showing gross interest and Korean tax withheld. Available at bank counter or online banking portal.
• Korean bank account statements(거래 내역서) — showing all transactions including interest credits and tax withholding deductions for the full calendar year.
• 적금 만기지급명세서 — for installment savings accounts: maturity payment statement showing total principal, interest, and tax withheld.
• Maximum balance documentation — the highest balance reached at any point during the year for FBAR reporting. Can be found in monthly account statements; identify the month with the highest balance.
• Exchange rate source — screenshot or printout from IRS.gov yearly average rates page, or Federal Reserve historical rate source, documenting the rate used for conversion.
• Residency start date documentation — passport entry stamps, I-94 records, or visa records confirming the first U.S. presence date (for split-year interest apportionment).

Common Mistakes 자주 발생하는 오류

• 1 Misidentifying the Korean withholding rate breakdown as "15% national + 0.4% local." The correct breakdown is 14% national income tax (소득세) + 1.4% local income tax (지방소득세 — which is 10% of the national tax) = 15.4% combined. This error appears in many tax guides. The total rate (15.4%) is correct, but the components matter for documentation and for claiming both components on Form 1116.
• 2 Filing Form 1116 in the general basket instead of the passive basket for Korean bank interest. Korean bank interest is passive income — it must be reported on Form 1116 using the "Passive" income category, not "General Limitation." Using the wrong basket produces an incorrect FTC limitation calculation and may result in the credit being disallowed during IRS examination.
• 3 Reporting all 적금 maturity interest as fully taxable when the 적금 opened before U.S. residency began. If an installment savings account opened before the residency start date matures after residency begins, only the portion of interest accrued during the residency period is taxable in the U.S. The pre-residency accrued interest is not reportable — but requires an apportionment calculation.
• 4 Answering "No" on Schedule B Part III while holding Korean accounts. Any U.S. tax resident with Korean financial accounts must check "Yes" on Part III question 7a — regardless of account balance. Checking "No" is a false statement on a federal return and can be used as evidence of willfulness in FBAR enforcement. The Part III question has no dollar threshold — it covers any foreign financial account of any balance.
• 5 Not reporting Korean bank interest because it is a small amount. There is no minimum threshold below which foreign interest becomes non-reportable. Even $5 of Korean bank interest must be included on Schedule B. The IRS receives Korean account data through FATCA/IGA reporting — omitting small amounts creates a mismatch between the taxpayer's return and IRS-received data.
• 6 Not claiming the Foreign Tax Credit for Korean tax withheld. Every dollar of Korean bank interest withholding (15.4%) is creditable on Form 1116 against U.S. tax on the same interest. Reporting the Korean interest income on Schedule B but omitting Form 1116 results in paying full U.S. tax on income that Korea already taxed — unnecessary double taxation.
• 7 Using market or commercial bank exchange rates rather than the IRS yearly average rate. The IRS accepts the yearly average exchange rate published on its website as a standard method for converting foreign income. Using naver.com finance rates, commercial bank conversion rates, or year-end snapshot rates produces inconsistent and non-IRS-recognized conversion figures.
• 8 Treating Schedule B interest reporting as satisfying FBAR and FATCA obligations. Reporting Korean interest on Schedule B fulfills the income tax reporting obligation — it does not replace the separate FBAR (if accounts exceeded $10,000) or Form 8938 (if assets exceeded FATCA thresholds). All three obligations are independent and each must be fulfilled separately.

Hanmi CPA Insight