He Followed TSMC From Taiwan to Phoenix at 60. Social Security Said His 30-Year Career Had Just Begun.

Picture a semiconductor engineer who spent three decades on the fab floor in Hsinchu, then moved his family to Phoenix at 60 when TSMC (NYSE:TSM | TSM Price Prediction) asked him to help bring up its new Arizona operations. He assumes his long career in Taiwan will count toward U.S. Social Security once he retires here. It generally will not, and the reason has nothing to do with how hard he worked.

This scenario is showing up more often as TSMC’s $265 billion U.S. commitment pulls experienced staff into a 12-facility Arizona footprint. On expat forums, late-career engineers ask the same question: I paid into a national system for 30 years, so what happens when I move? The answer applies to any immigrant professional arriving late from a country with no Social Security agreement with the U.S., whether the passport says Taiwan, India, China, Vietnam, or Brazil.

The One Rule That Decides Everything: Totalization

Social Security eligibility runs on a credit system. A worker needs 40 credits, roughly 10 years of covered employment, to qualify for a retirement benefit. You can earn up to four credits per year, and only wages with U.S. Social Security payroll tax withheld count toward that total.

To help people who split careers across borders, the Social Security Administration (SSA) maintains totalization agreements. These treaties let a worker combine coverage from both countries to reach the 40-credit threshold and prevent employers and employees from paying Social Security taxes to two governments on the same paycheck. The U.S. has these agreements with roughly 30 countries, including Japan and South Korea. Taiwan is not on that list.  For a worker from a non-agreement country, foreign work history is invisible to the U.S. system. Thirty years of covered employment in Taipei counts as zero credits in Phoenix.

Consider our engineer’s timeline. Starting U.S.-covered work at 60 and needing roughly 10 years of covered earnings means he would have to work on a U.S. payroll until about age 70 just to qualify for the minimum benefit. If he retires at 65, or if TSMC keeps him on a Taiwan payroll without U.S. Social Security withholding, he may finish his career with no U.S. benefit at all, regardless of what he paid into Taiwan’s Labor Insurance and Labor Pension programs.

How This Reshapes the Rest of the Retirement Plan

If U.S. Social Security is off the table or produces only a small check, other pieces have to carry more weight. That usually means leaning harder on personal savings, an employer 401(k) started late in the career, any Taiwan pension he qualifies for, and a spouse’s benefits if the spouse has a longer U.S. work record. A spouse eligible on her own record can also open the door to spousal benefits for him later, even without his own 40 credits.

Taxes matter too. Taiwan pension income received by a U.S. tax resident is generally reportable to the IRS, and the interaction with U.S. brackets can be unpleasant if no one plans for it. The 2.8% Social Security cost-of-living adjustment for 2026 is a reminder that the U.S. benefit, once earned, is inflation-protected in a way most foreign pensions are not. Missing out on that inflation hedge is the quiet cost of falling short of 40 credits.

What to Actually Do Before Retiring

1. Confirm your country’s status. Check the SSA’s published list of totalization-agreement countries before assuming your foreign years will help. If your home country is not on it, plan as if those years do not exist for U.S. purposes.
2. Nail down whose payroll you are on. A U.S. assignment funded through a foreign entity may not trigger U.S. Social Security withholding, which means no credits are accruing even while you work in Phoenix. Ask HR in writing.
3. Plan both systems separately. Claim what you earned in your home country under its rules, and build a U.S. plan around savings, spousal benefits, and any covered years you can realistically accumulate.

A career can cross an ocean overnight. Its retirement credits may stay behind. Before making a late-career move, find out which system each paycheck is building and whether the years on opposite sides of the border can ever meet.

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