U.S.–Taiwan Tax Planning for TSMC Transferees

Residency first

Your tax status comes from dates and facts, not your badge

A TSMC transfer does not by itself determine your U.S. tax status. Residency can arise under the green-card or substantial-presence tests — each with exceptions and elections that require individual analysis — and Arizona layers on its own factual standards.

Once you are a U.S. person, worldwide income and foreign financial accounts can create reporting even when money never enters the United States. So keep a travel calendar and immigration records; payroll withholding and a mailing address are evidence, not the complete legal conclusion. The account inventory comes next.

Worldwide inventory

Which foreign accounts can trigger U.S. reporting

As a U.S. person you may have reporting obligations for foreign financial accounts and specified foreign assets — even without a single transfer. Foreign mutual funds, pensions, insurance and companies can have specialized U.S. tax treatment of their own.

Inventory each item’s legal owner, institution, account type, maximum value, income and underlying holdings, and let a cross-border tax professional determine the required forms. Then connect the inventory to your pay.

• Taiwan bank and brokerage accounts
• Foreign funds and individual securities
• Pension or labor-retirement interests
• Insurance with cash value
• Property and rental income
• Business or trust interests

Compensation

Match every payment to where and when you earned it

Salary, bonuses, equity and relocation payments may relate to services performed across more than one location or period. Payroll reporting is a starting record, not a complete cross-border conclusion.

Here is how it plays out: an award that vests across your move date can touch both countries’ systems at once. Foreign tax credits or domestic rules may still reduce double taxation, but qualified professionals must apply them to your facts — and as the next section shows, a tax treaty is not something to count on here.

Retain assignment letters, pay statements, award agreements and travel records, and coordinate federal and Arizona withholding with your projected tax.

U.S. accounts

Decide now how your 401(k) works if Taiwan calls you home

A 401(k) or IRA may remain useful after a move, but check provider access, address policy, investment availability and distribution withholding before leaving the United States.

IRS guidance states that plan distributions to foreign payees generally face 30% withholding unless documentation establishes U.S.-person status or another valid exception. The IRS treaty list does not include Taiwan as of this review, so if you later reside in Taiwan, do not assume treaty-rate relief — professional analysis is essential.

One shared file

Build the cross-border file both tax teams will ask for

Keep one shared timeline and document set for both jurisdictions: travel, work location, payroll, awards, account ownership, maximum values, income and taxes paid. Your financial plan organizes the cash and investments; the U.S. and Taiwan professionals decide filing, reporting and legal treatment from the same facts.

Use the file as preparation, not as individualized advice — current plan documents control your U.S. accounts, and cross-border professionals should make the residency and reporting calls.

• Establish your federal and Arizona residency from documented facts
• Map each piece of compensation to its work location and vesting period
• Inventory your foreign accounts and specified foreign assets
• Assign who prepares each return and information form
• Review transfers, sales and retirement distributions before they occur