For most US savers, the question “should I hold a foreign currency deposit?” has a short answer: probably not. Top 6-month USD CDs in May 2026 sit around 4.0-4.2% APY (with promotional outliers a touch higher), competitive with most retail foreign currency deposit yields on a risk-adjusted basis, and the tax reporting overhead (FBAR, Form 8938, foreign tax credit) usually outweighs marginal yield differences. The question changes meaningfully for non-US residents — Korean savers in particular can hold 6-month USD deposits in the roughly 3.9-4.3% range with materially different tax treatment for FX gains, and Japanese savers can access 4-6% USD yields through campaigns and net banks. This piece looks at where USD CDs make sense for US savers, why FX deposits work better elsewhere, and the compliance landmines that catch US residents holding foreign accounts. (Rates and FX levels move daily — verify with the issuing bank or a live source before acting.)
US savers: top 6-month CDs around 4% APY is the baseline
Six-month USD certificate of deposit rates as of early May 2026 (representative published APYs — verify with the bank before opening):
| Bank | 6-Month CD APY (approx.) | Minimum | Early Withdrawal Penalty |
|---|---|---|---|
| Marcus by Goldman Sachs | ~4.00% | $500 | 90 days interest |
| Ally Bank | ~3.30% | $0 | 60 days interest |
| Capital One 360 | ~3.90% | $0 | 3 months interest |
| Limelight Bank | ~4.15% | $1,000 | 3 months interest |
| Schwab Brokered CDs | ~4.20% | $1,000 | Sell on secondary market |
A $10,000 deposit at 4.0% APY for 6 months yields roughly $200 before tax — at a 24% federal bracket, about $152 after federal (state varies). HYSA rates run slightly below the top CD rates (often 3.5-4.0%) but offer liquidity. For a US saver with no foreign currency need, this is the comparison set, not foreign currency products.
The interest tool handles the CD vs HYSA compare panel directly — you can stack 6-month and 12-month CDs against current HYSA rates and see after-tax outcomes side by side.
Why foreign currency deposits exist for non-US savers
In Korea and Japan, retail USD deposits are common products because the home currency is exposed to FX risk against the dollar. A Korean saver holding 100% KRW assets is fully exposed to KRW depreciation (USD/KRW around the 1,470 level in early May 2026); allocating 10% to USD provides natural diversification. The same logic applies to Japanese savers facing yen weakness (USD/JPY around the mid-150s).
For these savers, USD foreign currency deposits provide:
- Exposure to USD interest rates (roughly 3.9-4.3% in Korea; 4-6% in Japan via campaigns and net banks, while megabank posted rates are very low)
- FX gain potential if the home currency weakens further
- Natural hedge against import inflation (oil, food, electronics)
US residents have the opposite default: their entire economic life is dollar-denominated, so adding more USD exposure provides no diversification.
FX gain taxation differs sharply across markets
The same product — a 6-month USD deposit yielding ~$200 in interest — produces very different tax outcomes by jurisdiction.
| Market | FX Gain Tax | Interest Tax | Effective Reporting |
|---|---|---|---|
| US (foreign deposit, US resident) | Ordinary income (varies by bracket) | Ordinary income + FBAR/8938 (when thresholds met) | Heavy |
| Korea (USD deposit, individual) | Tax-free | 15.4% withholding (separate); aggregated into global income tax if total interest+dividends exceed ₩20M/year | Light |
| Japan (米ドル外貨預金, individual) | Miscellaneous income; income tax filing required if non-employment misc income exceeds ¥200K/year | 20.315% separate withholding | Medium |
Korea’s tax-free FX gain treatment for individual deposits is the most generous of the three; Japan’s ¥200K miscellaneous income threshold means smaller balances often produce no tax liability. For US residents holding foreign deposits, FX gains are ordinary US income regardless of foreign tax treatment, and reporting requirements add real compliance cost.
US residents holding foreign accounts: PFIC and FBAR
If you’re a US person (citizen, green card holder, or resident for tax purposes) and you hold any foreign financial account exceeding $10,000 aggregate at any point during the year, you must file FBAR (FinCEN Form 114). Penalties for non-willful failure start at $10,000 per violation; willful violations can reach $100,000 or 50% of the account balance.
Additional reporting:
- Form 8938 (FATCA): Required if foreign assets exceed $50K-$200K depending on filing status and residency
- Schedule B: Foreign interest reported as ordinary US income
- Form 1116: Foreign tax credit to offset double taxation on interest withheld abroad
- Form 8621 (PFIC): Required for foreign mutual funds and ETFs, but generally not for plain bank deposits
The compliance cost — typically $500-$2,000 in cross-border CPA fees annually — often exceeds the yield advantage of holding foreign deposits over US-domiciled alternatives.
What about USD deposits at non-US banks for US residents?
Some US savers consider holding USD-denominated accounts at foreign banks (e.g., a Singapore or Hong Kong bank offering 4.5% on USD). The yield comparison rarely justifies the friction:
| Approach | Yield (USD, 6M, approx.) | Tax Reporting | FDIC/Insurance |
|---|---|---|---|
| US bank USD CD | ~4.0% APY | Form 1099-INT | FDIC up to $250K |
| Brokered CD | ~4.2% APY | Form 1099-INT | FDIC (per issuing bank) |
| Foreign bank USD account | ~4.0-5.0% | FBAR + Form 8938 (when thresholds met) | Foreign deposit insurance only |
| US Treasury bill (6M) | ~4.0-4.3% yield | State-tax-free interest | Direct US Treasury obligation |
Brokered CDs and Treasury bills typically beat foreign accounts on after-tax return without the compliance burden. The narrow case for foreign accounts is operational — paying foreign expenses, receiving foreign income — not yield arbitrage.
Non-US savers: the 10% foreign allocation rule
Personal finance materials published by Korean and Japanese regulators and industry bodies (FSS, Financial Services Agency, banking associations) commonly cite roughly 10% of household financial assets in foreign currency as a typical diversification target. It’s a guideline, not a regulation, and households can adjust within roughly 5-20% based on risk tolerance. The point is diversification, not speculation: concentration above 20-30% turns the position into an FX bet rather than a hedge.
For a Korean household with ₩100M in cash assets, 10% is about $6,800 at 1,470 KRW/USD. For a Japanese household with ¥30M in liquid assets, 10% is roughly $19,000 at 156 JPY/USD. Adding more than this for “the dollar will keep rising” reasoning shifts from diversification to speculation. Inflation-adjusted thinking matters too: see inflation-real-rate-2026 for how nominal yields compress to real returns once inflation is netted out — a USD deposit at 4.0% with US inflation around 2.5% is a roughly 1.5% real return before FX moves are factored in.
Tool — model the deposit math
The interest tool compare panel handles USD CD scenarios at 3.5%, 4.0%, and 4.5% APY across 3-month, 6-month, and 12-month terms. After-tax outcomes adjust for federal-bracket and state-tax inputs. For non-US savers, multilingual versions handle KRW and JPY conversions with FX scenarios layered onto the underlying interest math.
The honest answer for US-based savers: stick with USD CDs, brokered CDs, or Treasury bills around 4.0-4.2% APY, none of which require FBAR reporting or foreign tax credits. For Korean and Japanese savers, USD deposits with home-country tax treatment offer something US savers can’t easily access — currency diversification at retail scale with favorable taxation. The 10% foreign allocation rule keeps the position diversifying rather than speculative. Run your specific scenario in the interest tool to see how the math works for your situation, including the cases where the answer is “leave it in your home currency.” (Yields, FX rates, and tax thresholds change — confirm the current numbers with the bank, the IRS/FinCEN, or the relevant tax authority before acting.)