Leaving the US for Singapore With RSUs: Why 'No Tax Treaty' Is the Detail Everyone Misses

The offer from Singapore looked like a raise. It was. Then the W-2 arrived.

Alex had been at his US tech company for four years. His Singapore office sent an offer: same company, regional role, bigger scope. He looked at Singapore's top income tax rate and compared it to what he was paying. He ran the math on a napkin and said yes.

Six months in, his US employer sent a W-2. Box 1 showed $340K in wages. He didn't understand it. He'd been paid $140K in the US for January and February before he left. But the W-2 showed $200K more than that.

His US equity team's email was three sentences. A batch of RSUs had vested in April, two months after he moved. His employer had sourced a portion of those RSUs to the US, calculated on the workdays he'd spent in the US during the four-year vesting period. That US-sourced portion: $200K, ordinary income, taxed at US marginal rates. The Singapore tax rate he'd been excited about? Applied to his Singapore salary, not to those RSUs.

He called his US CPA. Asked if the FEIE would cover it. No, she said. RSUs from a US employer are not foreign earned income. The Foreign Earned Income Exclusion applies to compensation for services performed in a foreign country. The RSU sourcing calculation runs on workdays, not on where you're physically sitting when the shares vest. You worked for those shares partly in the US. The US is taking its cut.

Singapore has no capital gains tax. That's real. It does not help with this.

The Problem Most People Don't See Until the W-2 Arrives

The Singapore zero-tax story is accurate as far as it goes. Singapore levies no capital gains tax. Personal income tax rates top out at 24% on income above SGD 1M, and the effective rate on a $280K salary runs around 18-22%. Compared to California's combined federal and state burden of 50%+ at the top bracket, Singapore looks like a tax haven.

The part of the story that doesn't usually get told until it's too late: if you are a US citizen or hold a green card, you pay US federal income tax on your worldwide income regardless of where you live. Singapore's rates don't reduce your US tax bill. They reduce the Singapore portion of your tax bill. For income that the US claims jurisdiction over — which includes RSU income from a US employer, calculated using US workdays — you pay the US rate.

The US and Singapore have no income tax treaty. Every other major US expat destination has some version of a bilateral agreement. The UK treaty gives you mechanisms for avoiding double taxation on specific income types. The India treaty governs how retirement distributions are taxed. Singapore has nothing. The US and Singapore are treaty partners on estate tax but not on income tax. Every dollar of income subject to US tax gets taxed at full US domestic rates, with no treaty-based reduction and no treaty-based mechanism for resolving double taxation.

RSU Sourcing: The Calculation Your Equity Team Runs (Whether or Not They Tell You)

RSU income is sourced to the period of services between grant date and vest date. IRS guidance established this principle decades ago and it has been applied consistently to equity compensation ever since. The allocation is proportional to workdays, not residential days, and not the country where you happened to be sitting when the shares vested.

Here's the math on a typical case. Say you were granted 2,000 RSUs in January 2023, vesting ratably over four years (500 per year, or 125 per quarter). You moved to Singapore in March 2026. A vest happens in April 2026.

The total vesting period runs roughly 1,461 calendar days (January 2023 through January 2027). Your US workdays run from grant in January 2023 through your last US workday in February 2026 — approximately 785 workdays. Your Singapore workdays from March 2026 onward: roughly 30 by the April vest.

The US-sourced percentage for that April 2026 vest: 785 / (785 + 30) = approximately 96%. If the 125 shares vest at $80 per share ($10,000 total), the US claims roughly $9,600 as US-sourced ordinary income.

Now extend that over a full year of vesting in Singapore with four quarterly vests. As you accumulate Singapore workdays, the US-sourced percentage gradually declines — but it starts very high and only decreases slowly. In year one of a Singapore assignment, a meaningful majority of your RSU income is still US-sourced if you spent the prior three-plus years in the US.

Why FEIE Doesn't Help Here

The Foreign Earned Income Exclusion lets qualifying US citizens and resident aliens exclude up to $132,900 (2026 figure) of foreign earned income from US taxable income. If you meet either the bona fide residence test or the physical presence test for Singapore, you can claim the FEIE and reduce your US tax on your Singapore salary.

The limitation: FEIE covers foreign earned income. RSU income from a US employer is not foreign earned income. It's employment income, but it's US-sourced based on the grant-to-vest workday calculation. The IRS's position is that RSUs from a US company represent deferred compensation for services performed in the US during the vesting period. The FEIE doesn't reach into deferred compensation of this type.

What FEIE actually helps with in Singapore: your Singapore salary paid by a Singapore entity. If your employment contract has you on a Singapore payroll and your Singapore compensation is $200K, FEIE shelters $132,900 of it from US tax. The remaining $67,100 is US taxable, and you can't offset it with a Singapore Foreign Tax Credit because your effective Singapore rate on that income is low enough that the credit doesn't fully cover the US liability.

The combined picture for a senior tech employee moving to Singapore with significant unvested RSUs: you save on Singapore income tax (real), you potentially save some US tax via FEIE on the Singapore salary portion (partial, up to the exclusion cap), and you still owe US tax at your marginal rate on the US-sourced portion of your RSU income (unavoidable without treaty protection).

Whether the Singapore move is a tax win depends entirely on your RSU-to-salary ratio and how far through your vesting cycle you are when you move. For a senior engineer with $400K in unvested RSUs and a $180K salary, the RSU tax exposure can easily dwarf the FEIE savings.

The CPF Wrinkle for US Citizens on Local Payroll

Singapore's Central Provident Fund is a mandatory social security savings scheme. If you're employed in Singapore, your employer and you both contribute to CPF — employer at 17% of salary, employee at 20%, up to the ordinary wage ceiling.

The US-person complication: CPF contributions come from after-tax income. The US does not recognize CPF as a tax-deferred retirement account. Your employer's CPF contribution on your behalf may be US-taxable as additional compensation depending on the employment structure. Your own CPF contributions don't reduce your US taxable income. And CPF balances accumulate inside the Singapore system — your US employer withholding doesn't account for this.

Whether you're on a US payroll or a Singapore payroll matters here. US employees on a Singapore employer-of-record structure generally do have CPF obligations. US citizens on a direct US payroll transfer don't. Your employment structure determines your CPF exposure. This is worth confirming before the move, not six months after.

The Social Security interaction is simpler: the US and Singapore don't have a totalization agreement. That means US citizens working in Singapore may owe FICA contributions in both countries on the same income depending on employment structure. If you're on a US payroll deployed to Singapore, you likely still owe FICA. If you're on a Singapore payroll, you likely don't. Get the employment structure in writing before you agree to the offer terms.

What to Decide Before You Accept the Offer

The Singapore offer has specific financial questions that need answers before you sign, not after you land.

Your current US-sourced RSU percentage. Pull your RSU grant agreements. Note your grant date and vesting schedule. Calculate approximately how many workdays you have accumulated in the US since each grant. That ratio — US workdays to total workdays in the vesting period — is the US-sourced percentage for unvested shares. On a large grant with years remaining, this number may be 70%, 80%, or higher. Multiply it by the unvested value to understand your US tax exposure that moves to Singapore with you.

Whether your employer applies sourcing allocation correctly. Ask your employer's equity or payroll team: when RSUs vest while I'm based in Singapore, will you apply a workday-based sourcing allocation to determine the US-withheld and Singapore-reported income? Get the answer in writing. If they say they'll treat all vest income as Singapore-sourced, you'll be under-withheld and will owe US tax at filing. If they say they'll withhold on 100% as US income, you'll be over-withheld and file for a refund. Either way, you need to know their approach before the first vest.

Your FEIE coverage on the salary. Model the FEIE election for your Singapore salary specifically. If your Singapore salary is $220K and the FEIE ceiling is $132,900, you'll shelter about 60% of your salary from US tax. The remaining $87,100 is US-taxable. For most employees with significant unvested equity, the FEIE savings on salary are real but modest compared to the RSU exposure.

Whether to sell vested shares before leaving. If you have vested shares and you're planning to move, selling them before you leave is clean. You're a US resident, you pay capital gains rates (15% or 20% depending on income level), and the Singapore period doesn't complicate the sourcing. Once you're a Singapore-based non-resident alien, selling US shares triggers 30% withholding if you're not a US citizen. For non-citizen H-1B holders moving to Singapore, selling vested shares before departure can save significant withholding complexity.

After You Arrive: What Doesn't Change

FBAR still applies. You're a US citizen or resident with foreign financial accounts. If your Singapore bank account balance exceeds $10,000 at any point in the year — and it will if you're receiving salary there — you file FinCEN 114. The filing obligation doesn't pause because you're in Singapore. It runs as long as you have qualifying foreign accounts.

Form 1040 still applies. US citizens file regardless of where they live. You'll use FEIE for the Singapore salary, Form 1116 for any Singapore tax credits available, and you'll report your RSU income on the 1040 using the sourcing allocation your employer provides. If your employer provides no allocation, you're responsible for calculating and reporting it correctly.

Your US brokerage account stays where it is. Don't open a Singapore brokerage account and start buying Singapore-domiciled funds. Singapore-domiciled ETFs and mutual funds are PFICs for US persons — the same trap that catches NRIs with Indian mutual funds. The complexity and punitive tax treatment of PFIC holdings isn't worth the convenience. Keep your US-listed investments in a US account. You can manage it from Singapore.

The 401K question: if you're on a US payroll, you can likely keep contributing during the Singapore deployment. If you move to a Singapore payroll, your 401K contributions typically stop (you're no longer receiving US W-2 wages). Either way, don't close or cash out the 401K on departure. Leave it where it is. The accounts continue to grow tax-deferred. You'll sort out the distribution strategy when you're closer to retirement.

The Honest Tax Picture

Singapore is a lower-tax environment than the US for most income types. That's a real benefit. What changes the calculation for US-citizen tech employees is the combination of worldwide taxation, no treaty, and RSU sourcing.

A non-US-citizen who moved from Germany to Singapore would pay German exit taxes and then be done with Germany. Singapore imposes no ongoing worldwide tax. For that person, the move is genuinely a tax simplification.

For a US citizen with unvested RSUs at a US company: you carry your US tax obligation with you. Singapore lowers your rate on Singapore-sourced income. It doesn't affect the US claim on income the US sources to itself. No treaty means no protective mechanisms. FEIE helps on salary, not on equity.

Whether the move is worth it depends on the numbers specific to your situation, not on the narrative. Run the RSU sourcing calculation on your unvested position. Understand your FEIE coverage on salary. Model your effective combined tax rate on total compensation in Singapore versus the US. Some people run these numbers and find the Singapore move still pencils out. Others find the RSU tax tail is large enough that the timing of the move matters more than the destination.

Alex's situation wasn't a catastrophe. His total 2026 US tax liability was higher than expected, but not ruinous. What he said afterward was more to the point: he would have negotiated his equity refresh differently if he'd understood that vesting in Singapore with a mostly-US-sourced grant was going to generate a large US tax event. He would have asked for a cash allowance rather than more RSUs. He didn't know to ask.

That's the question to ask before you accept. Not "what's the tax rate in Singapore." But "what happens to my existing equity if I vest it from there."