Ready for Tax Season 2027? The Cross-Border Family Document Checklist
Cross-border returns often run late because of missing foreign documents, not hard U.S. forms. Records from China, such as bank statements and property deeds, often take the longest to obtain, so starting in January keeps the April 15, 2027 deadlines realistic and makes an extension a choice rather than a necessity. The checklist below covers both U.S. and China records.
Short answer
Cross-border returns are often delayed by missing foreign documents, not by U.S. forms. Use the list below to collect U.S. and China records in January, so that the April 15, 2027 deadlines for the return, FBAR and Form 3520 are realistic, and extensions are a choice rather than a necessity.
Key facts and figures
- Q4 2026 estimated tax is due January 15, 2027, federally and in California (Form 1040-ES, FTB 540-ES).
- Returns, FBAR and Form 3520 are generally due April 15, 2027, with extensions to October 15, 2027 (IRS, Form 3520 instructions).
- FBAR values use the Treasury year-end rate; income uses a consistently applied rate, such as the IRS yearly average (FinCEN, IRS).
- China-side records (statements, tax certificates, deeds) take the longest to gather, so start in January.
Key dates for the 2027 filing season
| Date | What | Source |
|---|---|---|
| January 15, 2027 | Q4 2026 federal and California estimated tax | IRS, FTB |
| February 1, 2027 | Employers furnish 2026 Forms W-2 | IRS |
| April 15, 2027 | Form 1040 and Form 540 (with Form 8938 if required); FBAR; Form 3520 (calendar-year individuals; filed separately from the return) | IRS, FTB, IRS FBAR, IRS 3520 |
| October 15, 2027 | Extended returns; FBAR automatic extension; extended Form 3520 | Form 4868, IRS |
An extension extends time to file, not time to pay (FTB).
U.S. documents
- Forms W-2 (note the new box 12 codes, including TT and TP for overtime and tips, on 2026 forms; see 2026 information-reporting changes).
- Forms 1099-INT, 1099-DIV, 1099-B and consolidated brokerage statements; 1099-K if payment-app sales were more than $20,000 and more than 200 transactions (IRS).
- Form 1098 mortgage interest, property tax bills, and charitable receipts.
- Estimated tax payment confirmations, federal and California.
- K-1s from partnerships or S corporations, including any California PTE elective tax credit (PTET guide).
China and other foreign documents
- Every foreign account: bank name, account number, and the highest balance during 2026, including wealth products. Whether stored-value apps such as Alipay, WeChat Pay and Yu'e Bao count as FBAR accounts is not settled by clear FinCEN guidance, so report conservatively (which accounts count). Foreign assets may also need Form 8938 (FATCA), which is filed with your return, has different thresholds than FBAR (for example $50,000 at year end for an unmarried U.S. resident, higher abroad), and generally uses the same Treasury rate (Form 8938 instructions).
- Foreign income: interest, dividends, rent and salary statements, plus the Chinese tax payment certificates (完税证明) that support a foreign tax credit.
- Property: purchase and sale contracts, deeds, and expense records for any China property sold or rented.
- Gifts and inheritances received: dates, amounts and the giver's relationship to you; Form 3520 is generally required if gifts or bequests from nonresident individuals or foreign estates, including gifts from related people (parents, grandparents and relatives add up), exceed $100,000 for the year. Once you cross the threshold, each gift over $5,000 is identified separately. Form 3520 is filed separately from your income tax return (Form 3520 instructions, Rev. Dec. 2025). See our Form 3520 guide.
- Foreign companies or funds: financial statements if you own 10% or more of a foreign corporation, or are an officer or director of one in which a U.S. person owns 10% or more, since Form 5471 generally applies in those cases (Form 5471 instructions); and fund statements for possible PFICs, which are reported on Form 8621 (Form 8621 instructions).
- Days: travel dates for anyone whose residency is in question (B-2 parents, first-year green card).
Exchange rates
For FBAR, and generally for Form 8938, convert each account's maximum value at the Treasury rate for the last day of the calendar year (FinCEN; Treasury rates). For income and expenses, the IRS says it has no official rate and generally accepts any posted rate used consistently, and it publishes yearly averages (IRS).
Illustrative example (illustrative numbers)
China rent of ¥60,000 received evenly through the year. For illustration only, at the IRS 2025 yearly average of 7.129 yuan per dollar, that is about $8,416. The 2026 average was not yet published as of October 15, 2026; use the 2026 figure when available, and use the same method each year.
Family and household items
- SSNs or ITINs for everyone on the return; a spouse abroad may need an ITIN, for example for a joint return (nonresident spouse guide).
- Gifts to a spouse who is not a U.S. citizen: the 2026 annual exclusion is $194,000 instead of $19,000, for outright present-interest gifts that would otherwise qualify for the marital deduction (Rev. Proc. 2025-32; see 2026 family gifts).
- Childcare provider details and education expenses.
- Records of 2026 gifts you made above $19,000 per person (2026 family gifts).
Prior-year gaps
If you find accounts or income that were left off earlier returns, address them before filing 2026. Our Streamlined filing guide explains the options. For the federal changes that apply to 2026 returns, see OBBBA 2026.
Sources and last verified: Oct 15, 2026. Instructions for Form 3520 (Rev. Dec. 2025); Instructions for Form 5471 (Rev. Dec. 2025); Instructions for Form 8938; FinCEN FBAR instructions; Rev. Proc. 2025-32; IRS yearly average exchange rates page (updated Sep 17, 2026; 2026 average not yet published); FTB due dates page.
Frequently asked questions
When are 2026 individual returns due?
Generally April 15, 2027, the 15th day of the 4th month after year end (Pub. 519). Form 4868 extends filing, not payment, generally by 6 months to October 15, 2027 (Form 4868). California grants an automatic extension to October 15 with payment still due in April (FTB).
When is the 2026 FBAR due?
April 15, 2027, with an automatic extension to October 15, 2027 (IRS).
When is Form 3520 due for gifts received in 2026?
For calendar-year individuals, generally the income tax return due date, April 15, 2027, or the 15th day of the 10th month if the income tax return is extended (Form 3520 instructions).
Which exchange rate should I use?
For FBAR maximum values, the Treasury rate for the last day of the calendar year (FinCEN). For income, the IRS has no official rate and generally accepts any posted rate used consistently; it publishes yearly averages (IRS).
When will I get my W-2 and 1099s?
Employers must generally furnish 2026 Forms W-2 by February 1, 2027 (W-2 instructions). Most 1099s follow a similar early-February schedule.
Get started
If you would like a personalized checklist and a secure place to upload documents, you are welcome to book a consultation. See our cross-border family tax services.
Primary sources
General information, not tax advice or legal advice. Dates for 2027 are computed from current rules; confirm against 2027 IRS and FTB publications when released.